Examkin

Soru

Zorluk: OrtaCommon Ports and Protocols

A network administrator is troubleshooting an issue where secondary DNS servers are unable to complete full zone transfers from the primary master DNS server across an internal firewall boundary. Standard client host name lookup queries across the firewall operate successfully. Which transport layer protocol and port number must be permitted on the firewall to allow zone transfers to complete?

  1. TCP port 53Cevap
  2. B
    UDP port 53
  3. C
    TCP port 5353
  4. D
    UDP port 67

Cevap

TCP port 53 must be permitted on the firewall to support DNS zone transfers.
DNS relies on TCP port 53 for zone transfers between primary and secondary name servers. Because zone replication involves transferring entire domain database files, it exceeds the 512-byte payload threshold of standard UDP DNS messages and requires the connection-oriented reliability, error recovery, and packet sequencing provided by TCP.

Adım Adım Çözüm

1
Analyze the functional difference between DNS queries and DNS zone transfers.
Standard queries use UDP port 53 for fast, lightweight resolution, whereas zone transfers replicate entire zone database files.
Zone transfers contain large volumes of records that exceed the traditional 512-byte UDP limit and require reliable connection-oriented delivery.
2
Identify the protocol and port utilized specifically for zone transfer operations.
DNS uses TCP port 53 for zone replication between primary and secondary servers.
TCP ensures complete and error-free transmission of large database records across network boundaries.

Anahtar Kavram

DNS Transport Layer Operations (TCP vs UDP Port 53)
Tahmini Süre:1m 30s
Bu soruyu puanla

Konular

Common Ports and Protocols

Bu konudan daha fazla soru