To All, I have DNS debug logging activated and the queries and replies are saved to a text file. However, there are a few categories of entries that i'm not sure what the mean. Here are some example lines.......... 10:22:58 64c packet udp rcv 1.1.1.x 5900 Q [0001 D NOERROR] domain.com 10:22:58 64c packet udp snd 1.1.1.x 5900 R Q [0085 A DR NOERROR] domain.com 10:22:58 64c packet udp rcv 1.1.1.x C590 Q [0001 D NOERROR] domain.com 10:22:58 64c packet udp snd 1.1.1.x C590 R Q [0085 A DR NOERROR] domain.com 10:22:58 64c packet udp rcv 1.1.1.x 6876 Q [0001 D NOERROR] domain.com 10:22:58 64c packet udp snd 1.1.1.x 6876 R Q [0085 A DR NOERROR] domain.com The columns with 5900, R, Q, & DR i have not clue in their representation. The reason i am looking at the logs is because i need to know the details of a smtp communication as it relates to DNS. Thx alot.

as i read them they are just informational. udp packets and transport with no errors. once smtp knows destination its done with dns

thx for reply well i am looking at the logs because i'm not sure where my mailserver is getting my fqdn from, since there is not rDNS lookup in the logs. Also, how do i know which applications are making dns queries? There are SERVFAIL logged and i know which machine they are coming from, but dont' know which process is making the queries.