Thanks... the issue was, in fact, in resolv.conf.
On Wed, Oct 30, 2013 at 9:31 AM, Wietse Venema <wie...@porcupine.org> wrote: > Roman Gelfand: >> Looking at the tcp stream, below, of a smtp conversation, it appears >> there is 5 second delay before the actual smtp conversation begins. >> Is this normal behavior. If not, any ideas what/where specifically, >> in networking, I should be troubleshooting? No change was done to the >> server or any other machines on the network. This started happening >> all of a sudden. >> >> 15047 02:57:33.441270000 192.168.0.209 192.168.0.239 TCP 66 54398 > >> smtp [SYN] Seq=0 Win=8192 Len=0 MSS=1460 WS=4 SACK_PERM=1 >> 15048 02:57:33.441494000 192.168.0.239 192.168.0.209 TCP 66 smtp > >> 54398 [SYN, ACK] Seq=0 Ack=1 Win=14600 Len=0 MSS=1460 SACK_PERM=1 >> WS=16 >> 15049 02:57:33.441515000 192.168.0.209 192.168.0.239 TCP 54 54398 > >> smtp [ACK] Seq=1 Ack=1 Win=65700 Len=0 >> 15237 02:57:38.461112000 192.168.0.239 192.168.0.209 SMTP 97 S: 220 >> pmx1.mydomain.biz ESMTP Postfix > > It takes 5 seconds to look up the SMTP client hostname for 192.168.0.239. > > - Turn off chroot per DEBUG_README instructions. > > - Fix /etc/resolv.conf. > > - Fix /etc/hosts. > > - Fix /etc/host.conf. > > - Fix the DNS zone for 0.168.192.in-addr.arpa > > Wietse
