Examkin

Inside Source NAT and PAT Configuration and Verification

46 soru

Tüm türler46Çoktan seçmeli24Çoklu seçim10Kısa cevap12
Soru 1Soru →

To permit multiple internal private hosts to share the single public IPv4 address assigned to the GigabitEthernet0/0/0 WAN interface, which Cisco IOS command correctly implements Port Address Translation (PAT) for traffic permitted by Access Control List 15?

Cevabı ve açıklamayı göster

Cevap: ip nat inside source list 15 interface GigabitEthernet0/0/0 overload

Cevap

The command 'ip nat inside source list 15 interface GigabitEthernet0/0/0 overload' correctly enables Port Address Translation (PAT).
The command specifying 'ip nat inside source list 15 interface GigabitEthernet0/0/0 overload' correctly binds the access list to the egress interface and appends the 'overload' keyword, which enables Port Address Translation (PAT) so multiple internal devices can share a single public IPv4 address.

Adım Adım Çözüm

1
Identify the requirement for Port Address Translation (PAT)
Multiple internal hosts sharing a single public interface IP requires PAT (overload).
PAT uses unique source port numbers to track connections for multiple internal hosts behind a single IP address.
2
Formulate the Cisco IOS PAT interface command syntax
The correct command structure is 'ip nat inside source list <acl> interface <interface> overload'.
The 'inside source list' parameter references the internal traffic ACL, 'interface' specifies the egress IP source, and 'overload' enables port multiplexing.

Anahtar Kavram

Port Address Translation (PAT) Interface Overload Configuration
Soru 2Soru →

A network administrator is setting up Port Address Translation (PAT) on a Cisco IOS router using a public address pool named `PAT_POOL` and Access Control List `5`. Which two commands are required to correctly establish PAT and configure the LAN interface to participate in address translation? (Select two.)

Geçerli olan tümünü seçin

Cevabı ve açıklamayı göster

Cevap: ip nat inside source list 5 pool PAT_POOL overload; ip nat inside

Cevap

The two required commands are 'ip nat inside source list 5 pool PAT_POOL overload' entered in global configuration mode and 'ip nat inside' entered under the LAN interface configuration mode.
Configuring Port Address Translation (PAT) with an IP pool requires appending the 'overload' parameter to the global 'ip nat inside source list' command. Additionally, the internal interface connected to the local network must be identified with the interface-level command 'ip nat inside'.

Adım Adım Çözüm

1
Identify the global configuration command for pool-based PAT
Determine that 'ip nat inside source list 5 pool PAT_POOL overload' is required to map inside local hosts matching ACL 5 to the PAT_POOL while enabling port overloading.
The 'overload' keyword allows multiple private internal IP addresses to share public IP addresses in the pool by tracking unique TCP/UDP port numbers.
2
Identify the interface configuration command for internal boundary identification
Select 'ip nat inside' on the LAN interface.
Cisco IOS routers require explicit designation of NAT boundaries to determine where packet translation takes place.

Anahtar Kavram

Inside Source Port Address Translation (PAT) configuration requiring the overload keyword and inside interface designation.
Soru 3Soru →

A network engineer is configuring Port Address Translation (PAT) on a Cisco IOS router using an IP NAT pool named `INTERNET_POOL` for internal endpoints matched by access list `10`. Which global configuration command correctly enables PAT using this address pool?

Cevabı ve açıklamayı göster

Cevap: ip nat inside source list 10 pool INTERNET_POOL overload

Cevap

The command 'ip nat inside source list 10 pool INTERNET_POOL overload' correctly enables Port Address Translation using the specified pool.
The correct command uses 'ip nat inside source list 10 pool INTERNET_POOL overload'. The 'inside source' parameter specifies translation for outbound traffic originating inside the network, 'list 10' identifies hosts permitted by ACL 10, 'pool INTERNET_POOL' designates the global address pool, and 'overload' enables port-level multiplexing (PAT) so multiple internal endpoints can share pool addresses simultaneously.

Adım Adım Çözüm

1
Identify the direction of translation.
Internal hosts initiating outbound connections require 'inside source' translation.
Inside source NAT translates private local IP addresses to public global addresses.
2
Identify the method of matching source addresses and defining the public addresses.
Access list 10 filters inside local hosts, and the named pool 'INTERNET_POOL' defines the public IPv4 addresses.
The 'list 10 pool INTERNET_POOL' syntax binds the ACL host match condition to the pool range.
3
Determine the keyword required for Port Address Translation (PAT).
Adding the 'overload' keyword enables multiplexing multiple internal hosts onto pool addresses using unique TCP/UDP port numbers.
Without 'overload', Cisco IOS restricts dynamic NAT to a strict 1-to-1 IP address mapping.

Anahtar Kavram

Port Address Translation (PAT) configuration using dynamic address pools in Cisco IOS
Tahmini Süre:1m 0s
Soru 4Soru →

An administrator needs to configure Port Address Translation (PAT) on a Cisco IOS router so that all internal hosts on the subnet 172.16.50.0/24172.16.50.0/24 can access the Internet using the IPv4 address assigned to the WAN interface GigabitEthernet0/1. Interface GigabitEthernet0/0 connects to the internal LAN. Which configuration set correctly accomplishes this requirement?

Cevabı ve açıklamayı göster

Cevap: interface GigabitEthernet0/0
ip nat inside
!
interface GigabitEthernet0/1
ip nat outside
!
access-list 15 permit 172.16.50.0 0.0.0.255
ip nat inside source list 15 interface GigabitEthernet0/1 overload

Cevap

The command sequence configuring GigabitEthernet0/0 as ip nat inside, GigabitEthernet0/1 as ip nat outside, ACL 15 matching 172.16.50.0 0.0.0.255, and 'ip nat inside source list 15 interface GigabitEthernet0/1 overload' correctly enables PAT.
The correct command set properly sets GigabitEthernet0/0 as the inside interface and GigabitEthernet0/1 as the outside interface, specifies standard ACL 15 to match the 172.16.50.0/24 subnet, and uses the 'overload' keyword with the egress interface to enable Port Address Translation (PAT).

Adım Adım Çözüm

1
Identify and designate the NAT interfaces
GigabitEthernet0/0 is configured with 'ip nat inside' (internal LAN) and GigabitEthernet0/1 is configured with 'ip nat outside' (WAN interface).
Cisco IOS NAT requires specifying directionality on interfaces to know where translation occurs.
2
Define an Access Control List (ACL) matching internal private IPs
Access-list 15 matches subnet 172.16.50.0 with wildcard mask 0.0.0.255.
The ACL identifies which internal source IP addresses are eligible for address translation.
3
Configure PAT using interface overloading
Execute 'ip nat inside source list 15 interface GigabitEthernet0/1 overload'.
The 'overload' keyword enables Port Address Translation (PAT), allowing multiple internal hosts to share the single IP address assigned to the egress interface by tracking layer 4 port numbers.

Anahtar Kavram

Port Address Translation (PAT) Configuration using Interface Overload
Tahmini Süre:1m 15s
Soru 5Soru →

A network engineer is troubleshooting internet connectivity issues on a Cisco IOS router configured for Network Address Translation. Internal hosts on the 10.10.10.0/2410.10.10.0/24 network report that only one host can access external resources at any given time. Subsequent host traffic is dropped. The engineer inspects the router configuration and operational state using verification commands:

text
Router# show ip nat statistics
Total active translations: 1 (0 static, 1 dynamic, 1 extended)
Outside interfaces:
GigabitEthernet0/1
Inside interfaces:
GigabitEthernet0/0
Hits: 48 Misses: 12
CEF Translated packets: 48, Fast Switched packets: 0
Expired translations: 15
Dynamic mappings:
-- Inside Source
[id 1] access-list 101 pool INTERNET-POOL refcount 1
pool INTERNET-POOL: netmask 255.255.255.252
start 203.0.113.1 end 203.0.113.1
type generic, total addresses 1, allocated 1 (100%), misses 12

Router# show running-config | include ip nat
ip nat pool INTERNET-POOL 203.0.113.1 203.0.113.1 netmask 255.255.255.252
ip nat inside source list 101 pool INTERNET-POOL
access-list 101 permit ip 10.10.10.0 0.0.0.255 any

Which configuration change is required to allow all internal hosts on the 10.10.10.0/2410.10.10.0/24 network to share the single public IPv4 address simultaneously?

Cevabı ve açıklamayı göster

Cevap: Append the overload keyword to the command ip nat inside source list 101 pool INTERNET-POOL.

Cevap

Appending the overload keyword to the statement ip nat inside source list 101 pool INTERNET-POOL converts dynamic 1-to-1 NAT into Port Address Translation (PAT), enabling multiple internal hosts to share a single public IP address using unique source port numbers.
The command output indicates that the NAT pool contains only one IP address (203.0.113.1) and is 100% allocated without overload enabled. Because the overload keyword was omitted from the inside source translation statement, Cisco IOS performs dynamic 1-to-1 translation. Appending the overload keyword enables Port Address Translation (PAT), allowing multiple inside hosts to share the single IP address by using unique Layer 4 port numbers.

Adım Adım Çözüm

1
Analyze the output of show ip nat statistics and show running-config.
The pool INTERNET-POOL contains 1 total public IPv4 address (203.0.113.1). Allocation shows 1 allocated (100%) with 12 misses, indicating address pool exhaustion.
Without port multiplexing, dynamic NAT performs strict 1-to-1 mapping. Once all pool addresses are allocated, subsequent translation requests fail.
2
Identify the missing keyword in the NAT translation command.
The configuration entry ip nat inside source list 101 pool INTERNET-POOL lacks the overload keyword.
The overload keyword instructs Cisco IOS to track Layer 4 source port numbers (PAT), enabling thousands of concurrent internal connections over a single IP address.
3
Formulate the correct configuration fix.
Reconfigure the router statement to ip nat inside source list 101 pool INTERNET-POOL overload.
This modification resolves translation misses and allows all hosts on the 10.10.10.0/24 network to share 203.0.113.1 simultaneously.

Anahtar Kavram

Port Address Translation (PAT) Overload Configuration
Soru 6Soru →

A network administrator is configuring Port Address Translation (PAT) on an enterprise Cisco IOS router. The internal subnets matched by Access Control List 15 require multiple internal IP addresses to share a dynamic pool of public IPv4 addresses named GUESTNATPOOLGUEST_NAT_POOL. Which Cisco IOS global configuration command correctly enables PAT using this dynamic address pool?

Cevabı ve açıklamayı göster

Cevap: ip nat inside source list 15 pool GUEST_NAT_POOL overload

Cevap

The correct command to configure dynamic PAT using an IP address pool is 'ip nat inside source list 15 pool GUEST_NAT_POOL overload'.
The correct command syntax for dynamic NAT with PAT using an IP address pool is 'ip nat inside source list <acl-number> pool <pool-name> overload'. The 'overload' keyword enables Layer 4 source port tracking so multiple internal IP addresses can share the IP addresses in the pool simultaneously.

Adım Adım Çözüm

1
Identify the source direction and dynamic NAT type
Inside source traffic matching an ACL requires 'ip nat inside source list <ACL>'.
Internal private hosts initiating outbound connections must undergo inside source NAT.
2
Specify the target public address pool
Append 'pool GUEST_NAT_POOL' to map matching ACL traffic to the designated pool.
The scenario requires using a pre-defined named pool of public IP addresses instead of a single interface.
3
Enable port multiplexing (PAT)
Append the 'overload' keyword at the end of the command.
Without 'overload', Cisco IOS configures standard dynamic NAT (1-to-1 translation), whereas PAT (many-to-one/many-to-few using layer 4 ports) explicitly requires 'overload'.

Anahtar Kavram

Port Address Translation (PAT) pool configuration using the overload keyword
Soru 7Soru →

A network engineer on router R1 configures dynamic Network Address Translation using an IP pool containing two public addresses (203.0.113.1203.0.113.1 to 203.0.113.2203.0.113.2) to service the internal subnet 172.16.10.0/24172.16.10.0/24. Access Control List 10 permits traffic from 172.16.10.0/24172.16.10.0/24. The router configuration includes the statement `ip nat inside source list 10 pool NAT_POOL`. During peak operating hours, users report that after two simultaneous connections are established, all additional internal hosts fail to reach external destinations. Output from `show ip nat statistics` displays active translations at maximum pool capacity with zero port translation entries. Which configuration change will allow all internal hosts to share the public addresses concurrently?

Cevabı ve açıklamayı göster

Cevap: Append the `overload` keyword to the `ip nat inside source list 10 pool NAT_POOL` command.

Cevap

Append the `overload` keyword to the `ip nat inside source list 10 pool NAT_POOL` command to enable Port Address Translation (PAT).
The command `ip nat inside source list 10 pool NAT_POOL` without the `overload` keyword performs dynamic 1-to-1 NAT mapping. With only two IP addresses in the pool, only the first two internal hosts receive translations; all subsequent translation attempts fail once the pool is exhausted. Appending the `overload` keyword activates Port Address Translation (PAT), allowing thousands of connections from internal hosts to share the pool IP addresses by tracking unique L4 transport port numbers.

Adım Adım Çözüm

1
Analyze the existing NAT configuration and symptoms.
The statement `ip nat inside source list 10 pool NAT_POOL` configures standard dynamic 1-to-1 NAT. Since the pool contains only two public IP addresses (203.0.113.1203.0.113.1 and 203.0.113.2203.0.113.2), only two internal hosts can obtain translations concurrently.
Without port multiplexing, each host requires an entire public IP address, leading to pool exhaustion when a third host attempts to transmit.
2
Identify the required Cisco IOS keyword to allow port multiplexing.
The `overload` keyword enables PAT, mapping multiple private IP addresses to the same public IP address using distinct source port numbers.
Adding `overload` allows hundreds of simultaneous internal sessions to share the two pool IP addresses.

Anahtar Kavram

Port Address Translation (PAT) vs. Dynamic 1-to-1 NAT
Soru 8Soru →

A network engineer is configuring Port Address Translation (PAT) on a Cisco IOS router using an IP address pool. Access Control List 10 matches internal private IPv4 addresses, and the NAT pool is named `OUTSIDE_POOL`. To allow multiple internal hosts to share the addresses in `OUTSIDE_POOL` by multiplexing Layer 4 port numbers, which single keyword must be appended to the end of the `ip nat inside source list 10 pool OUTSIDE_POOL` command?

Cevabı ve açıklamayı göster

Cevap: overload; the overload keyword

Cevap

overload
Appending the keyword `overload` to the `ip nat inside source list <acl> pool <pool_name>` command enables Port Address Translation (PAT). This allows Cisco IOS to translate both IP addresses and transport layer port numbers, enabling many internal private IP addresses to share public IP addresses in the pool.

Adım Adım Çözüm

1
Identify the requirement for Port Address Translation (PAT) using an IP address pool.
Standard dynamic NAT assigns public IP addresses to private IP addresses on a one-to-one basis.
Without port tracking, dynamic pool NAT runs out of available public IPv4 addresses when internal hosts exceed the pool size.
2
Determine the necessary Cisco IOS command modifier to enable port multiplexing.
Appending the keyword `overload` instructs the router to track transport-layer port numbers (PAT).
The `overload` keyword enables multiple internal sockets to share pool addresses simultaneously.

Anahtar Kavram

Inside Source Port Address Translation (PAT) Pool-based Configuration
Tahmini Süre:1m 0s
Soru 9Soru →

A network administrator configures Port Address Translation (PAT) on a Cisco IOS router to allow hosts on the 192.168.10.0/24192.168.10.0/24 internal subnet to access external servers using a dynamic NAT pool. After applying the configuration, only the first host to send traffic successfully establishes an outbound connection. All subsequent internal hosts fail to reach external destinations.

The router configuration is as follows:
text
ip nat pool EDGE_POOL 198.51.100.10 198.51.100.10 netmask 255.255.255.252
access-list 105 permit ip 192.168.10.0 0.0.0.255 any
ip nat inside source list 105 pool EDGE_POOL
!
interface GigabitEthernet0/0
ip address 192.168.10.1 255.255.255.0
ip nat inside
!
interface GigabitEthernet0/1
ip address 198.51.100.9 255.255.255.252
ip nat outside

Which modification to the router configuration will resolve the connectivity failure for all remaining internal hosts?

Cevabı ve açıklamayı göster

Cevap: Append the overload keyword to the ip nat inside source list 105 pool EDGE_POOL command.

Cevap

Appending the overload keyword to the ip nat inside source statement enables Port Address Translation (PAT), allowing multiple inside local addresses to share the single IP address configured in the pool.
The correct response identifies that the 'overload' keyword is missing from the NAT translation statement. When configuring dynamic NAT with a pool containing a single IP address, omitting 'overload' causes the router to perform standard dynamic 1-to-1 NAT rather than PAT. The first internal host consumes the single IP address in the pool (198.51.100.10198.51.100.10). All subsequent hosts fail to obtain a translation entry because the pool is exhausted. Appending 'overload' enables port multiplexing, allowing up to ~65,000 simultaneous connections to share the single pool address.

Adım Adım Çözüm

1
Analyze the existing dynamic NAT pool configuration.
The command 'ip nat pool EDGE_POOL 198.51.100.10 198.51.100.10 netmask 255.255.255.252' defines a pool containing exactly one usable public IP address (198.51.100.10198.51.100.10).
Understanding pool size identifies how many simultaneous dynamic 1-to-1 translations can occur.
2
Evaluate the translation command 'ip nat inside source list 105 pool EDGE_POOL'.
Without the 'overload' keyword, Cisco IOS performs dynamic 1-to-1 NAT instead of Port Address Translation (PAT).
Dynamic 1-to-1 NAT allocates one public IP per active internal host. Once the single IP address in EDGE_POOL is allocated to the first host, the pool is exhausted and subsequent host requests are dropped.
3
Determine the required command modification to allow port multiplexing.
Appending 'overload' to the command ('ip nat inside source list 105 pool EDGE_POOL overload') enables PAT, multiplexing multiple internal hosts across different source port numbers on the single public IP 198.51.100.10198.51.100.10.
PAT allows thousands of concurrent translations on a single IP address by leveraging transport-layer port tracking.

Anahtar Kavram

Port Address Translation (PAT / NAT Overload) using dynamic IP pools
Tahmini Süre:2m 0s
Soru 10Soru →

A network engineer is troubleshooting outbound connectivity failures on a Cisco IOS router. Internal devices on subnet 10.0.10.0/2410.0.10.0/24 can establish a maximum of two concurrent Internet connections. Additional hosts experience connection timeouts. The output of `show ip nat statistics` displays:

Total active translations: 2 (0 static, 2 dynamic, 0 extended)
Outside interfaces: GigabitEthernet0/1
Inside interfaces: GigabitEthernet0/0
Hits: 842 Misses: 412
Dynamic mappings:
-- Inside Source
[id 1] access-list 10 pool PUBLIC_POOL refcount 2
pool PUBLIC_POOL: netmask 255.255.255.252
start 198.51.100.1 end 198.51.100.2
type generic, total addresses 2, allocated 2 (100%), misses 412

The current running configuration contains `ip nat inside source list 10 pool PUBLIC_POOL`.

Which configuration change on the router will allow all internal hosts on subnet 10.0.10.0/2410.0.10.0/24 to share the existing pool addresses concurrently without adding new public IP addresses?

Cevabı ve açıklamayı göster

Cevap: Append the overload keyword to the ip nat inside source list 10 pool PUBLIC_POOL command.

Cevap

Append the overload keyword to the ip nat inside source list 10 pool PUBLIC_POOL command.
Appending the overload keyword to the inside source pool configuration enables Port Address Translation (PAT). Under PAT, Cisco IOS tracks Layer 4 source port numbers in extended translation entries, allowing multiple internal hosts to simultaneously share a small pool of public IP addresses.

Adım Adım Çözüm

1
Analyze the show ip nat statistics output
The pool PUBLIC_POOL has a total of 2 addresses, both are allocated (100%), and 412 misses have occurred.
Without PAT, dynamic NAT allocates public IP addresses from the pool on a 1-to-1 basis. Once all addresses in the pool are exhausted, subsequent translation requests fail.
2
Identify the missing Port Address Translation (PAT) parameter
The running configuration shows `ip nat inside source list 10 pool PUBLIC_POOL` without the `overload` keyword.
Without `overload`, Cisco IOS performs standard dynamic 1-to-1 NAT rather than PAT (many-to-1 or many-to-few multiplexing using L4 port numbers).
3
Determine the corrective configuration command
Update the command to `ip nat inside source list 10 pool PUBLIC_POOL overload`.
The `overload` keyword enables PAT, allowing thousands of internal sockets to share the 2 public IP addresses in the pool simultaneously.

Anahtar Kavram

Port Address Translation (PAT) with NAT Pools
Soru 11Soru →

A network engineer is configuring Port Address Translation (PAT) on a Cisco IOS router using a dynamic interface-based configuration. The engineer enters the following global configuration command to map inside addresses matched by Access List 10 to the GigabitEthernet0/1 interface:

`ip nat inside source list 10 interface GigabitEthernet0/1`

Which single Cisco IOS keyword must be added to the end of this command to allow multiple internal hosts to share the single public IP address using unique source port numbers?

Cevabı ve açıklamayı göster

Cevap: overload

Cevap

overload
The `overload` keyword instructs Cisco IOS to perform Port Address Translation (PAT). PAT enables multiple inside local IP addresses to share a single inside global IP address (such as a router's outside interface address) by distinguishing traffic flows with unique source port numbers.

Adım Adım Çözüm

1
Identify the goal of the configuration command.
The objective is to enable Port Address Translation (PAT) using the router interface's single public IPv4 address.
Without PAT enabled, dynamic NAT only performs 1-to-1 IP translations, which exhausts the single interface IP address after only one internal host translates.
2
Determine the required Cisco IOS command parameter for PAT.
Adding `overload` to the end of the `ip nat inside source` statement enables port-level multiplexing.
The `overload` keyword tells Cisco IOS to track Layer 4 TCP and UDP port numbers alongside IP addresses, allowing thousands of simultaneous internal connections on a single public IP.

Anahtar Kavram

Port Address Translation (PAT) Overload Keyword
Tahmini Süre:45s
Soru 12Soru →

A network administrator is configuring Port Address Translation (PAT) on a Cisco IOS router to allow multiple internal hosts on the 192.168.1.0/24 subnet to share the single public IPv4 address assigned to the GigabitEthernet0/1 interface. The administrator enters the following CLI commands:

Router(config)# access-list 1 permit 192.168.1.0 0.0.0.255
Router(config)# ip nat inside source list 1 interface GigabitEthernet0/1

During testing, only the first internal host that generates outbound traffic successfully connects to the Internet. Subsequent traffic from all other internal hosts is dropped. Which configuration change resolves this issue and enables all internal hosts to share the interface IP address simultaneously?

Cevabı ve açıklamayı göster

Cevap: Append the overload keyword to the ip nat inside source list 1 interface GigabitEthernet0/1 command.

Cevap

Appending the overload keyword to the NAT configuration command resolves the issue by enabling Port Address Translation (PAT).
In Cisco IOS, specifying a NAT inside source list with an interface but without the overload keyword configures dynamic 1-to-1 NAT using only the IP address of that interface. Because only one IP address is available, only the first host receives a translation entry in the NAT table. Appending the overload keyword enables Port Address Translation (PAT), allowing the router to distinguish traffic from multiple internal hosts using unique source port numbers.

Adım Adım Çözüm

1
Analyze the existing NAT command
The command 'ip nat inside source list 1 interface GigabitEthernet0/1' configures dynamic 1-to-1 NAT without port multiplexing.
Without the 'overload' keyword, Cisco IOS binds the single IP address of GigabitEthernet0/1 to the first inside local IP address requesting translation.
2
Identify the cause of traffic drop for subsequent hosts
Once the single outside IP address is allocated to the first host, no additional public IP addresses are available in the pool.
Standard dynamic NAT requires one unique public IPv4 address per active internal host.
3
Apply the correction for Port Address Translation (PAT)
Executing 'ip nat inside source list 1 interface GigabitEthernet0/1 overload' enables PAT.
The 'overload' keyword instructs the router to track source port numbers along with IP addresses, allowing up to 65,000+ simultaneous internal connections on a single public IP address.

Anahtar Kavram

Port Address Translation (PAT) Overload Keyword Requirement
Soru 13Soru →

A network administrator is configuring Port Address Translation (PAT) on a Cisco IOS router. Internal private IP hosts defined in Access Control List 1 (ACL 1) must share the single public IPv4 address assigned to the GigabitEthernet0/0 interface when communicating with the internet. Which Cisco IOS global configuration command correctly enables PAT for this scenario?

Cevabı ve açıklamayı göster

Cevap: ip nat inside source list 1 interface GigabitEthernet0/0 overload

Cevap

The command 'ip nat inside source list 1 interface GigabitEthernet0/0 overload' correctly configures PAT using an egress interface's IPv4 address.
The command 'ip nat inside source list 1 interface GigabitEthernet0/0 overload' specifies that traffic matching ACL 1 coming from the inside interface should have its source address translated to the IP address configured on GigabitEthernet0/0. The inclusion of the 'overload' keyword enables Port Address Translation (PAT), allowing multiple internal devices to simultaneously share the single public IP address via layer 4 port tracking.

Adım Adım Çözüm

1
Identify the translation direction and source identifier.
Internal traffic is identified by ACL 1, requiring 'ip nat inside source list 1'.
Inside source NAT identifies traffic originating from the internal network for translation.
2
Specify the target public IP source.
The target is the address on interface GigabitEthernet0/0, using 'interface GigabitEthernet0/0'.
When a dedicated public IP pool is not available or the ISP dynamically assigns an interface IP, NAT maps traffic directly to that interface.
3
Enable port-level multiplexing (PAT).
Append the 'overload' keyword at the end of the statement.
The 'overload' keyword allows thousands of internal IP addresses to share a single public IP address by tracking unique TCP/UDP source port numbers.

Anahtar Kavram

Configuring Inside Source Port Address Translation (PAT) with an interface address
Soru 14Soru →

A network administrator needs to verify the operational summary of Network Address Translation (NAT) on a Cisco IOS router, including active translation totals, hit/miss counters, expired translations, and dynamic pool usage. Which Cisco IOS EXEC command displays these summary statistics?

Cevabı ve açıklamayı göster

Cevap: show ip nat statistics; show ip nat statistic

Cevap

The correct command is show ip nat statistics.
The show ip nat statistics command provides a summary view of NAT operations on a Cisco IOS router. It displays the total number of active translation entries, the count of inside and outside interfaces, memory allocation, pool configuration ranges, and hit/miss counters.

Adım Adım Çözüm

1
Identify the required NAT verification output
The requirement calls for operational summary metrics such as total active translations, hit/miss counts, and pool allocations rather than individual translation table entries.
Different EXEC commands serve distinct verification purposes in Cisco IOS.
2
Determine the appropriate Cisco IOS EXEC command
The command show ip nat statistics provides the summary metrics, interface designations, and pool configurations.
The show ip nat translations command lists active dynamic/static mappings, whereas show ip nat statistics summarizes overall NAT health and performance.

Anahtar Kavram

Cisco IOS NAT/PAT Verification Commands
Tahmini Süre:1m 0s
Soru 15Soru →

An enterprise router is configured to perform dynamic NAT for an internal LAN subnet using a NAT pool containing a single public IP address (203.0.113.2203.0.113.2). Network users report that while the first host connecting to an external server successfully establishes a session, all subsequent internal hosts fail to reach external destinations simultaneously.

Review the following excerpt from the router's configuration:

text
interface GigabitEthernet0/0
ip address 10.50.0.1 255.255.255.0
ip nat inside
!
interface GigabitEthernet0/1
ip address 203.0.113.1 255.255.255.248
ip nat outside
!
ip access-list standard LAN_SERVERS
permit 10.50.0.0 0.0.255.255
!
ip nat pool PUBLIC_POOL 203.0.113.2 203.0.113.2 netmask 255.255.255.248
ip nat inside source list LAN_SERVERS pool PUBLIC_POOL

Which configuration change will resolve the issue and permit concurrent internet access for multiple internal hosts?

Cevabı ve açıklamayı göster

Cevap: Append the overload keyword to the ip nat inside source list LAN_SERVERS pool PUBLIC_POOL command.

Cevap

Append the overload keyword to the ip nat inside source list LAN_SERVERS pool PUBLIC_POOL command.
Appending the 'overload' keyword to the dynamic NAT statement transforms the mapping from dynamic 1-to-1 NAT into Port Address Translation (PAT). PAT multiplexes multiple internal IP addresses onto a single public inside global address by varying the layer 4 source port numbers, thereby permitting concurrent sessions for all LAN hosts.

Adım Adım Çözüm

1
Analyze the configuration and symptoms.
The statement 'ip nat inside source list LAN_SERVERS pool PUBLIC_POOL' lacks the 'overload' keyword, which instructs Cisco IOS to perform dynamic 1-to-1 NAT rather than 1-to-many PAT.
Dynamic 1-to-1 NAT allocates one public IP address from the pool per host. Because the pool contains only one IP address (203.0.113.2), only one device can be translated at any given time.
2
Identify the required NAT operational mode for single IP multi-host sharing.
Port Address Translation (PAT / NAT Overload) allows thousands of concurrent flows to share one public IP address by assigning unique source port numbers.
Adding the 'overload' keyword at the end of a dynamic NAT mapping command explicitly enables PAT.
3
Formulate the correct Cisco IOS CLI command modification.
Execute 'ip nat inside source list LAN_SERVERS pool PUBLIC_POOL overload' in global configuration mode.
This resolves port translation allocation and permits all internal hosts matching ACL LAN_SERVERS to reach external networks concurrently.

Anahtar Kavram

Inside Source NAT and PAT (Overload) Pool Configuration
Tahmini Süre:2m 0s
Soru 16Soru →

A network administrator configures dynamic NAT on a Cisco IOS router to enable hosts on the 192.168.10.0/24192.168.10.0/24 internal network to reach the Internet using an address pool defined as 203.0.113.1203.0.113.1 to 203.0.113.2203.0.113.2. After deployment, only two internal hosts can access external servers at any given time. Subsequent connection attempts from other internal hosts fail until one of the active hosts disconnects. Verification with the command `show ip nat translations` shows exactly two active entries without any transport layer port numbers listed. Which configuration change must be made on the router to allow all internal hosts to access external resources simultaneously?

Cevabı ve açıklamayı göster

Cevap: Append the `overload` keyword to the `ip nat inside source list` configuration command.

Cevap

Appending the `overload` keyword to the `ip nat inside source list` command enables Port Address Translation (PAT), allowing multiple internal private IP addresses to share the public addresses in the pool by tracking unique source port numbers.
Omitting the `overload` keyword in a dynamic NAT pool configuration limits Cisco IOS to standard dynamic 1-to-1 address mappings. Because the public pool contains only two IP addresses, the first two active internal hosts occupy the entire pool. Appending the `overload` keyword enables Port Address Translation (PAT), allowing multiple inside local addresses to be multiplexed over the same inside global addresses using unique Layer 4 port numbers.

Adım Adım Çözüm

1
Analyze the symptoms described in the scenario
Only two hosts can connect simultaneously because the pool has only two IP addresses (203.0.113.1203.0.113.1 and 203.0.113.2203.0.113.2).
Without port multiplexing, dynamic NAT performs strict dynamic 1-to-1 mappings on a first-come, first-served basis.
2
Examine the verification command output details
`show ip nat translations` shows translation entries without port numbers (e.g., Inside local mapped directly to Inside global).
The absence of Layer 4 port numbers confirms that Port Address Translation (PAT) is disabled, causing IP address exhaustion after two host translations.
3
Identify the required Cisco IOS command syntax fix
Adding `overload` to `ip nat inside source list <acl> pool <pool_name> overload` enables PAT.
The `overload` keyword instructs the router to track source port numbers, allowing thousands of concurrent sessions over the shared public IP pool.

Anahtar Kavram

Port Address Translation (PAT) Overload Keyword Requirement
Soru 17Soru →

During network troubleshooting on router R3, users on subnet 172.16.10.0/24172.16.10.0/24 report that only one internal host can access the Internet at a time. The network administrator runs `show ip nat statistics` and observes the following output:

Total active translations: 1 (0 static, 1 dynamic, 0 extended)
Outside interfaces:
GigabitEthernet0/1
Inside interfaces:
GigabitEthernet0/0
Hits: 142 Misses: 18
Dynamic mappings:
-- Inside Source
access-list 15 pool CORP_PAT refcount 1

The running configuration contains:
`ip nat pool CORP_PAT 203.0.113.10 203.0.113.10 prefix-length 29`
`ip nat inside source list 15 pool CORP_PAT`

Which configuration change on R3 will resolve the issue and permit multiple internal hosts to access external resources simultaneously?

Cevabı ve açıklamayı göster

Cevap: Add overload to the end of the ip nat inside source list 15 pool CORP_PAT statement.

Cevap

Add overload to the end of the ip nat inside source list 15 pool CORP_PAT statement.
The output of `show ip nat statistics` shows '0 extended translations', confirming that standard dynamic 1-to-1 NAT is running instead of Port Address Translation (PAT). Because the NAT pool contains only a single public IPv4 address (203.0.113.10203.0.113.10), omitting the `overload` parameter limits translation to only one internal host at a time. Appending `overload` to the `ip nat inside source list` command instructs the router to track Layer 4 port numbers, enabling multiple internal hosts to share the single public address simultaneously.

Adım Adım Çözüm

1
Analyze the show ip nat statistics output.
Output shows 0 extended translations and 1 dynamic translation active.
An extended translation indicates PAT (layer 4 port tracking). Having 0 extended translations means standard 1-to-1 dynamic NAT is active.
2
Inspect the NAT pool and inside source command configuration.
The NAT pool CORP_PAT contains only one public IP address (203.0.113.10), and the translation rule lacks the overload keyword.
Without overload, standard dynamic NAT allocates the single pool address to the first host that generates traffic and exhausts the pool.
3
Determine the required CLI command modification.
Executing ip nat inside source list 15 pool CORP_PAT overload enables Port Address Translation.
Including overload allows multiple inside local IP addresses to share the single inside global IP address by tracking unique TCP/UDP port numbers.

Anahtar Kavram

Inside Source Port Address Translation (PAT) Configuration with NAT Pools
Tahmini Süre:2m 0s
Soru 18Soru →

To enable multiple internal devices to share the single public IPv4 address assigned to WAN interface Serial0/1/0 using Port Address Translation (PAT), which Cisco IOS command must be executed?

Cevabı ve açıklamayı göster

Cevap: ip nat inside source list 10 interface Serial0/1/0 overload

Cevap

The command 'ip nat inside source list 10 interface Serial0/1/0 overload' correctly configures PAT using an exit interface.
The correct command syntax for configuring Port Address Translation using an exit interface IP address is 'ip nat inside source list <acl-number> interface <interface-id> overload'. The overload keyword tells the router to track transport-layer port numbers to allow multiple private IP addresses to share a single public IP address.

Adım Adım Çözüm

1
Identify the source traffic matched by Access Control List 10.
Internal IPv4 traffic is designated for NAT translation.
The 'list 10' parameter specifies which source addresses undergo translation.
2
Specify the egress interface for translation.
The public IPv4 address of interface Serial0/1/0 is selected as the translation target.
The 'interface Serial0/1/0' clause tells the router to use the interface's dynamic or static public IP address.
3
Append the 'overload' keyword.
Port Address Translation (PAT) is enabled using transport layer port numbers.
The 'overload' keyword allows multiple internal sockets to share the single interface IP address simultaneously.

Anahtar Kavram

Port Address Translation (PAT) Interface Overload Configuration
Tahmini Süre:45s
Soru 19Soru →

A network engineer needs to configure static Port Address Translation (Port Forwarding) on a Cisco IOS router to allow public users on the Internet to access an internal HTTP web server. The internal web server is assigned private IPv4 address 10.1.1.5010.1.1.50 and listens on TCP port 8080. External connections should be directed to the router's public IPv4 address 203.0.113.10203.0.113.10 on TCP port 80808080.

What exact Cisco IOS global configuration command must be entered to establish this static NAT mapping?

Cevabı ve açıklamayı göster

Cevap: ip nat inside source static tcp 10.1.1.50 80 203.0.113.10 8080

Cevap

ip nat inside source static tcp 10.1.1.50 80 203.0.113.10 8080
The correct Cisco IOS command for configuring static Port Address Translation (port forwarding) follows the structure: 'ip nat inside source static <protocol> <local-ip> <local-port> <global-ip> <global-port>'. Therefore, entering 'ip nat inside source static tcp 10.1.1.50 80 203.0.113.10 8080' maps incoming connections on public TCP port 8080 to internal server 10.1.1.50 on port 80.

Adım Adım Çözüm

1
Identify the static NAT configuration prefix for inside source address translation.
The initial keywords are 'ip nat inside source static'.
Static translation maps a specific inside local socket to an inside global socket.
2
Specify the Layer 4 transport protocol.
Add the keyword 'tcp'.
Static PAT (port forwarding) requires defining whether TCP or UDP is being translated.
3
Specify the inside local IP address and port number.
Add '10.1.1.50 80'.
This defines the internal server's private socket (IP and service port).
4
Specify the inside global IP address and port number.
Add '203.0.113.10 8080'.
This defines the public IP and port presented to the external network.

Anahtar Kavram

Static Port Address Translation (Static PAT / Port Forwarding)
Soru 20Soru →

A network administrator is configuring Port Address Translation (PAT) on a Cisco IOS router. Internal hosts on subnet 10.45.10.0/2410.45.10.0/24 connect to interface `GigabitEthernet0/0/0`, while interface `GigabitEthernet0/0/1` connects to the Internet Service Provider. Standard access list 10 has been configured with `access-list 10 permit 10.45.10.0 0.0.0.255`. Which TWO configurations are required on the router to correctly enable inside source PAT sharing the public IPv4 address of `GigabitEthernet0/0/1`?

Geçerli olan tümünü seçin

Cevabı ve açıklamayı göster

Cevap: Execute `ip nat inside source list 10 interface GigabitEthernet0/0/1 overload` in global configuration mode.; Configure `ip nat outside` under interface configuration mode for `GigabitEthernet0/0/1`.

Cevap

The two required configurations are executing 'ip nat inside source list 10 interface GigabitEthernet0/0/1 overload' in global configuration mode and configuring 'ip nat outside' on interface GigabitEthernet0/0/1.
Configuring 'ip nat inside source list 10 interface GigabitEthernet0/0/1 overload' in global configuration mode combined with applying 'ip nat outside' to interface GigabitEthernet0/0/1 completes the mandatory steps to translate internal source traffic matching ACL 10 across the ISP interface using Port Address Translation.

Adım Adım Çözüm

1
Identify the required global configuration statement for interface-based PAT.
The command 'ip nat inside source list 10 interface GigabitEthernet0/0/1 overload' correctly binds ACL 10 to the WAN interface and specifies port overload.
The 'overload' keyword allows thousands of internal sockets to share the single IP address assigned to GigabitEthernet0/0/1 using distinct layer 4 port numbers.
2
Identify interface NAT boundary designations.
Interface GigabitEthernet0/0/0 requires 'ip nat inside', and external interface GigabitEthernet0/0/1 requires 'ip nat outside'.
Cisco IOS NAT routing decisions require explicit identification of which interfaces face the inside private network and which interface faces the outside public network.

Anahtar Kavram

Inside Source Port Address Translation (PAT) using an Interface
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Inside Source NAT and PAT Configuration and Verification Alıştırma Soruları — Cisco CCNA | Examkin