DNS ports and linux firewall
 

Hi
If a DNS server is using as a domain hosting so it should also initiated in a zone transfer. Is this logic is correct. If zone transfer has to be initiated which ports should be open and which sources for the zone transfer has to be chosen.

Is UDP port 53 only used as a dns resolution or it also should be opened outbound as that of tcp port 53 which is used for zone transfer.

Prot Src Dst Use
udp 53 53 Queries between servers (eg, recursive queries)
Replies to above
tcp 53 53 Queries with long replies between servers, zone
transfers Replies to above

http://www.faqs.org/faqs/internet/tc...ins-faq/part1/