Slow and sometimes failing Qmail

[erhnam]

My Qmail is slow and sometimes doesn't work. When I try to send a mail using my smtp server this always takes around 10 second. Sometimes the server rejects the request.

What have I tried:

- Added -Rt0 option
- Changed resolv.conf (only 127.0.0.1 and the dns from my ISP).
- Checked the Firewall

Anyone else with this problem? Or knows how to fix this?

 

[jamesyeeoc]

Do you have Plesk set for SMTP authentication?

You did mean 127.0.0.1 (not 127.0.01)?

Resolv.conf - you put the ISP's nameserver first, then the 127.0.0.1, right?

See if changing the MAXPERIP in your other post changes the delay or not.

What *nix distro and Plesk version are you running?

Are you on a VPS/Virtuozzo server or standalone/dedicated?

There are many other questions which could be asked... CPU, RAM, server load, # hosted domains, many many things.

 

[erhnam]

The plesk version I use is 7.5.2. The box contains RedHat9 and uses 1 GB mem and is installed with a Pentium 4 3 Ghz.

In the resolve.conf I put the localhost entry at the end.

I also changed back the MAXIP settings. But it seems it has nothing to do with this issue.

 

[erhnam]

I checked the /usr/local/psa/var/log/maillog and found this interesting:

Sep 27 11:33:23 server07 qmail-queue: dwlib[11699]: scan: the message(drweb.tmp.UeldeH) sent by [email protected] to [email protected] should be passed without checks, because contains uncheckable addresses.

I checked plesk and noticed that the service drweb is not running. Anyone?

 

[jamesyeeoc]

After you made the -Rt0 change, did you restart the service for it to take effect?

If you telnet to your server on port 25 and 110, do you still get a 10 second delay before seeing the 220 response?

I have seen the DrWeb errors, can be from either not having DrWeb running, not licensed properly (the 'free' version only covers the first 15 mail users or something like that), or not installed/configured properly. (there may be more possible causes, I disabled it on my servers because it is too costly and just not quite right IMO)

 

[jamesyeeoc]

I have also come across a thread where a delay was caused by a 1and1 hosting quirk where their MX server was being used first, and had to be re-configured in their CP to use the Plesk server as primary MX

http://forum.plesk.com/showthread.php?threadid=20306&highlight=qmail+AND+delay
(see the last post)

 

[erhnam]

Originally posted by jamesyeeoc
After you made the -Rt0 change, did you restart the service for it to take effect?

Yes, my /etc/xinetd.d/smtp_psa file looks now like this:

service smtp
{
socket_type = stream
protocol = tcp
wait = no
disable = no
user = root
instances = UNLIMITED
server = /var/qmail/bin/tcp-env
server_args = -Rt0 /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

If you telnet to your server on port 25 and 110, do you still get a 10 second delay before seeing the 220 response?

No, I do not get a 10 seconds delay when I try to reach it with telnet. Not from this machine. Not from other machines and also not from the webserver itself..

I checked the MX record 1-1 thread but I do not see any problems here.. Anyone else?

 

[erhnam]

I found this:

try increase que number of concurrente conections and disable reverse-lookups in DNS.

/usr/local/psa/qmail or /usr/local/psa/qmail/conf
and look for dot-qmail.files (.qmail files)

adjust the qmail files to work like you want.....

"G.10. DNS or IDENT lookups can make SMTP slow
If qmail-smtpd is slow to respond to connections, the problem is probably due to DNS reverse lookups or IDENT lookups. If you're starting qmail-smtpd with tcpserver, remove the "-h", "-p", and "-r" options and add "-H", "-P", "-R", and "-l hostname".

Any can tell me where to change this?

 

[jamesyeeoc]

The file you edited to add the -Rt0 option is where they are referring to (on a Plesk server). Not sure about using the -H, -P, and "-l hostname", never had to do that ever.

 

[erhnam]

This had something to do when you use tcpserver.. I'm not quite sure about this...

 

[jamesyeeoc]

If you're server is running a RH flavor, then smtp should be running as part of xinetd (which it is), and unless you have re-installed Qmail per the Qmail Rocks instructions or the generic Qmail instructions, then it will not be running under tcpserver. There are many ways to get Qmail running, the instructions you found do not totally apply to Plesk servers.

 

[erhnam]

Okee thanks for the info. What about:

DNS or IDENT lookups can make SMTP slow

Is there any way to disable this for qmail? And can you tell me what the impact would be when I disable this? I disabled it also for proftpd and the speed is very good now!

 

[jamesyeeoc]

First I would run a dnsreport.com on your domain and make sure there are no DNS issues which may be contributing. Since you had posted that telnet to the server has no delay, I'm wondering if there is a resolving issue with the domain.

 

[erhnam]

Okee I fixed the reverse DNS issue. There are no issues on dnsreport.com, only a few warnings. The smtp is still very slow.. Any clue?

 

[jamesyeeoc]

You never answered my question from way back, about resolv.conf and if you put the 127.0.0.1 AFTER the ISP nameserver IP. What other lines do you have in the file other than the 2 nameserver & IP lines?

 

[erhnam]

[root@ns1 root]# cat /etc/resolv.conf
nameserver 206.13.30.12
nameserver 206.13.29.12
nameserver 127.0.0.1
[root@ns1 root]#

 

[jamesyeeoc]

Hi fellow SBC user...

Ok that looks fine, you have the SBC-SD, then SBC-LA, then the localhost. So that is now ruled out as a source of the problem.

Since you are not getting the delay from telnetting to port 25, it's only when the email client actually tries to send a message, right?

Have you tried multiple email clients (OE, Outlook, Thunderbird, etc) and also from different ISP's?

I was going to suggest a traceroute, but since there is no 'connection' delay, that probably wouldn't show anything.

It is sounding more like an authentication delay.

 

[erhnam]

Originally posted by jamesyeeoc
Hi fellow SBC user...

Ok that looks fine, you have the SBC-SD, then SBC-LA, then the localhost. So that is now ruled out as a source of the problem.

Since you are not getting the delay from telnetting to port 25, it's only when the email client actually tries to send a message, right?

Have you tried multiple email clients (OE, Outlook, Thunderbird, etc) and also from different ISP's?

I was going to suggest a traceroute, but since there is no 'connection' delay, that probably wouldn't show anything.

It is sounding more like an authentication delay.

I tried almost everything. Multiple clients, Different ISP's but no good results. I only have this when I sent e-mails. IMAP, POP3, FTP is very fast! Maybe Qmail does some resolving or reverse dns lookups. Is there any way to check that and maybe disable this? I had the same problem for FTP but I disabled it by putting

IdentLookups off
UseReverseDNS off

in the proftpd.conf. This fixed the problem. I wonder if something like this also exists for qmail?

 

[jamesyeeoc]

Yes, I saw that in your earlier post. Other than the -Rt0 fix, I have never seen or heard of any other options related to DNS/Lookups/Ident with a Plesk version qmail installation.

If you have modified the standard qmail install which Plesk does, like having done "Life with Qmail" or a standard Qmail install, then you would probably be running it with tcpserver which has those additional options you posted earlier.

Are you running the Plesk version of Spamassassin, and what AntiVirus are you running on the server?

 

[erhnam]

I run a default plesk installation and didn't modify anything. I disabled Spamassasin and DrWeb to make sure this is not the issue.