lst_ho...@kwsoft.de wrote:
Zitat von Nataraj <incoming-post...@rjl.com>:
lst_ho...@kwsoft.de wrote:
Zitat von Nataraj <incoming-post...@rjl.com>:
lst_ho...@kwsoft.de wrote:
Zitat von Nataraj <incoming-post...@rjl.com>:
Hi,
I would appreciate any suggestions anyone can offer on the
following problem that I'm having with postfix...
I'm running postfix+pgsql-2.3.3-2.1.el5_2 on a CentOS 5.4
server. I see what looks likes a server in stress mode as
described in http://www.postfix.org/STRESS_README.html except the
odd think about it is that the server is not heavily loaded and I
sure can't see where it's exceeding any process limits. What's
even odder is it doesn't appear that the stress code is
implemented in this version.
If I telnet to port 25 I get an immediate SMTP greeting followed
in 10 seconds by
421 4.4.2 mymail.com Error: timeout exceeded
and the connection being closed.
The following maillog entry is logged:
May 3 16:44:06 mymail postfix/smtpd[22573]: timeout after CONNECT
from 173-12-149-200.client.myisp.com[173.12.149.200]
Why do you think your Postfix server is "stressed"?? The automatic
stress-dependant features are introduced in version 2.5 as far as
i know so your Postfix does not support -o stress at all. If you
only have 4 smtpd running and your server show greeting
immediately when telneting to port 25 all should be fine.
I don't think it is a stress condition. The problem is that it is
timing everything out. Further checking shows, it times out
inbound SMTP connections in like 3-4 seconds and fails outbound
deliveries to slow servers. The transports also timeout and bounce
messages.
Sorry i still don't understand what the problem is...
Are you concerned about "timeout after SOMETHING" messages in the logs?
Do you have problems with mails not arriving?
Do you have problems with mails not leaving?
Please try to explain, maybe with log data for a problematic mail.
Regards
Andreas
"fails outbound deliveries to slow servers." means there are problems
with outbound mail deliveries. Yes there are complaints of people
sending mail from the outside whose delivery is either delayed or
does not get through. This means there are problems with inbound
mail. An SMTP server that times out after 4 seconds of inactivity is
not reasonable given the possibility of delays in others mail systems
and on the internet.
Please show the relevant log entries for a failed delivery attempt
from connect until disconnect. Postfix has reasonable defaults and for
sure no 4s timeout.
The question that I am asking is what else can cause these timeouts
if there is no stress code in my current version of postfix?
The smtpd_<mumble>_timeout settings are relevant on postfix side. The
default for smtpd is 300s. If your settings are at default or far from
the values you are seeing you should check if some stateful firewall
in between drops "inactive" connections earlier. If this does not help
you should capture a tcpdump to see what is going on.
Regards
Andreas
Hi Andreas,
I did post my configuration parameters in my first message. I mentioned
that I had changed them, but had restored the defaults to see if that
would solve the problem. The smtpd_timeout was never changed from
300s. Here is a log of a failed outbound delivery. As I mentioned,
the sysadmin for this server told me they have an 18 second delay before
sending the greeting, which they've found effective at stopping
spambots. I've done crazier things myself, and I think that a properly
working mailserver should be able to deliver to them even if it is a bit
unfriendly. Certainly I was able to deliver to them before this problem
started.
May 2 05:22:32 aspen postfix/smtp[6575]: 4CF471D0200:
to=<xxx...@cs.rutgers.edu>, relay=mail.cs.rutgers.edu[128.6.4.3]:25,
delay=124076, delays=124072/0.05/4\
.3/0, dsn=4.4.2, status=deferred (conversation with
mail.cs.rutgers.edu[128.6.4.3] timed out while receiving the initial
server greeting)
It most definitely is valid to telnet to an smtp server and type
commands to test it. I've been doing this for years. It was only until
this problem came up that I am no longer able to do it because I can't
type fast enough before it times me out (unless I enable pipelining and
paste the commands).
I maintain the firewall and there are no logs of problems there. I'm
fairly certain this is the SMTP server. If a firewall was timing out
the connection postfix would not know that it was a timeout and would
not be able to log a timeout error.
penguin> telnet aspen 25
Trying 66.35.48.14...
Connected to aspen.
Escape character is '^]'.
220 aspen.rjl.com ESMTP vPostMaster
421 4.4.2 aspen.rjl.com Error: timeout exceeded
Connection closed by foreign host.
From this log of the telnet session, the 421 error comes from the smtp
server and running tcpdump is useless because the problem is at the SMTP
level and not at the TCP or IP level.
Thank you. I appreciate your efforts to help. I guess I will have to
dig into the code and see if I can figure out what is going on, but I
was hoping somebody else might have seen a problem like this that would
save me the efforts of debugging the code. I may try upgrading to a
more recent release of postfix first.
Nataraj
