30 secs delay for every SMTP connection

[jnarvaez]

Hi,

I'm having some delay trouble with every SMTP connection. If I do a telnet to my server on port 25, the connection is established but i have to wait about 30 secs to recieve the 220 response. However if I do the same from the local machine (telnet localhost 25) i get an instant response.

If I stop spamassassin and reconfigure mailscanner, I get an instant response again.

I tried the famous -Rt0 and restart xinetd but no effect. My resolv.conf contains nameservers from my ISP and 127.0.0.1

This is my smtp_psa:
service smtp
{
socket_type = stream
protocol = tcp
wait = no
disable = no
user = root
instances = UNLIMITED
server = /var/qmail/bin/tcp-env
server_args = -Rt0 /usr/sbin/rblsmtpd -r blackholes.mail-abuse.org /var/qmail/bin/relaylock /var/qmail/bin/qmail-smtpd /var/qmail/bin/smtp_auth /var/qmail/bin/true /var/qmail/bin/cmd5checkpw /var/qmail/bin/true
}

any help would be apreciated

[scott]

Thats definitely the correct config.

[jnarvaez]

then?? what's wrong?? any idea?

[scott]

no idea, maybe theres something upstream screwing up your connections.

[jnarvaez]

something really strange... i'm only having problems with SMTP, pop3 and other services work fine, and the problem is when spamassassin is running

[jnarvaez]

i raised the concurrency values but no effect, 30 secs to get the 220 response. But if I try from the same server I get an instant response.

[jamesyeeoc]

Are you running the SA from Scott's repos?

Do you have any other SA addons or other vendor's antispam products also on the server (4psa or others)?

What firewall (and related software) are you using, and have you tried temporarily disabling it and test connection speed?

[jnarvaez]

yes, i'm using scott SA and yes i tried to stop APF temporarily, i restarted xinetd and qmail without success. But today, i reboot my entire server and everything works fine now!

Thanks for your help!

[Snapdragon]

/usr/sbin/rblsmtpd -r blackholes.mail-abuse.org

You are bound to experience some delay when you use a DNSBL, while it checks the incoming IP against the list. To eliminate this part you can either whitelist your IP or remove the DNSBL temporarily. I use Spamhaus and it can take up to 20 seconds to get a connection... but is it ever worth it.