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**clementine** · 05-06-2012, 21:04

Originally posted by bill gates

/var/log/mail.log shows a lot of this messages "Jun 5 22:28:31 server1 sm-mta[13529]: q55ISVl7013529: localhost [127.0.0.1] did not issue MAIL/EXPN/VRFY/ETRN during connection to MTA-v4"
This messages keep coming, also when no events are triggered.

Chances are great these are side effect of Zabbix simple checks on server1 for smtp service, ie. simple tcp connect on porrt 25. sendmail expects some RFC compliant MUA to introduce itself using HELO or EHLO. It gets none of them, it is logged.

I am new to zabbix but, in order to get better diagnostic in you mail.log, I suggest that you disable the simple check for smtp which creates noise. Make some event to trigger notification message and try to see with tail -f what goes on the sendmail side.

Also check zabbix_server.log (I don't know if something useful about SMTP is put with default debug level).

Also check sendmail access table, localhost should be RELAY or OK, name resolution, usual suspects, etc...

Hope this helps.

**bill gates** · 08-06-2012, 03:20

Thanks Clementine,

I disabled checks on SMTP server, I stopped receiving new messages on /var/mail.log but nothing new appeared after stopping apache.

I checked sendmail access and found "localhost RELAY"

I put zabbix on debug mode, but found no new logs on zabbix server logs.

I keep receiving jabber alerts after stopping apache, but no email notification. ( Cannot connect to SMTP server [server] [*** Cannot connect to [server]:25 [Connection refused]])

What can be happening?

Thanks

**clementine** · 08-06-2012, 08:03

Hmmm, this is weird...

If you have no log in sendmail it looks like zabbix can't establish the smtp session.

In your original post, you provided the following log:

Cannot connect to SMTP server [server1.example.com] [*** Cannot connect to [server1.example.com]:25 [Connection refused]]

and now it is

Cannot connect to SMTP server [server] [*** Cannot connect to [server]:25 [Connection refused]]

Are you sure that zabbix can resolve the host name ?
How is your email media setup ?

Those questions may sound dumb but sometimes it happens we miss the right point and go south

**bill gates** · 08-06-2012, 20:01

Thanks Clementine,

I have created 2 media types, one using "server1.example.com" and the other "example.com" as SMTP server, for testing purposes, to see wich one works, but none of them works.

Today, I added another media type using "localhost" as SMTP server. It also doesn't work; I receive the same error Cannot connect to SMTP server - Connection refused, and no logs.

I checked the file /etc/mail/local-host-names and found only localhost. I added 2 lines with example.com and server1.example.com and tested again with the same error.

I own the domain "example.com" but I didn't pointed it to this server. I'm just using the IP address of the server. Does this has something to do? "uname" -n shows me "server 1". When I login to telnet port 25, the answer is "220 server1.runnerace.com

Any advice? How can I check if zabbix can resolve the hostname?

Thanks,

Federico

**clementine** · 08-06-2012, 20:37

Originally posted by bill gates

I checked the file /etc/mail/local-host-names and found only localhost. I added 2 lines with example.com and server1.example.com and tested again with the same error.

They have nothing to do with TCP session establishment problems. This file may contain host aliases for domains when acting as a central mail hub.

According to what you report, zabbix can't open a tcp connection on localhost port 25. I see two possible reasons for that:
1) sendmail doesn't listen on port 25 on the loopback interface but port 587 (MSA)
2) there is some tcp wrapper or firewall which doesn't grant the connection and does RST provoking.

=> I would check the socket table

Any advice? How can I check if zabbix can resolve the hostname?

Check with nslookup, check nsswitch, check resolv.conf.
If this is ok, perform a full stop of zabbix daemons in the same shell session, then start it and check.

What is puzzling here is that the error message tells that the TCP session can't be established like if the destination socket was closed while you tell you can telnet to it. This looks really weird to me.

"uname" -n shows me "server 1"

using *nix for decades, I never had a hostname with a blank character. This is an easy way to break scripts during macro substitution and expressions evaluations.

**bill gates** · 08-06-2012, 20:53

Thanks,

I'll just reinstall the OS and try again. This is out of my knowledge.

This time I will try using CentOS and install Zabbix using yum. I though I was missing something "easy", because I tried using 3 different OSs (Debian 5 and 6, and Ubuntu 10.4) and got the same error.

It's a VPS dedicated to Zabbix.

I appreciate your help Clementine. I'll report back and tell you if I can get it to work or not.

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Sendmail: connection refused - No mails sent

Sendmail: connection refused - No mails sent

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