Sendmail running slow on fast box
Posted on 2005-03-18
This is really wierd... i'm building out a new sendmail box to act as another secondary mail server for our network and the box is running great except for some wierd speed issues with sendmail.
The box is not open to the web and routing traffic yet but i have it open to a few IPs that i'm sending test messags from. The box has a load average of 0.00 since its not doing much and doesn't appear to have much network lag (i'm ssh'ed into it and i can type as fast as normal, no lag there).
Here is the issue though, whenever i telnet to it on port 25, it takes forever (like 15-20 seconds) to come back with the helo prompt. after that, if i do the mail from: and rcpt to:, after each command it lags up and hangs, and then kicks to the next line.
typing in mailq for a little bit in the CLI caused some wierd lag too but it doesn't appear to be doing that anymore.
When i was setting up sendmail on this box, i stole the config files from another secondary box that should have similiar settings (access,mailertable,relay-domains,local-host-names,sendmail.mc,sendmailcf) and i modified the sendmail.mc file to change all of the names over from the server1 to server2 and did a make -C /etc/mail on it. it looks like the config is ok, but something is going on.
at first i thought it would be DNS related (it might still be) because the resolv.conf file had a dead server in the first listing. i changed it and put my primary dns in the first one and time warners dns in the second line. but i'm still seeing lag (i'm a windows junkie so i dont know, but is there an equivalent of ipconfig /flushdns for unix? or is it even caching?)