Hi, My centos 4.4 fully updated is going to be used as a mail server. However I did something or i didn't do something and I need some assistance. You see, If I run sendmail in port 25, i can telnet localhost 25 fine. but if I telnet the machine from another machine, the port is refuse. So i tested by running other programs (one at a time) listening to port 25, I cant connect.
So It seems that something is blocking specifically port 25 to receive incoming connections.
Can I have some assistance as to where to look for a configuration mistake? Basically something has my port 25 blocked on the same machine. BTW iptables is not running.
Cheers,
On Mon, 2007-08-20 at 10:52 -0500, Erick Perez wrote:
Hi, My centos 4.4 fully updated is going to be used as a mail server. However I did something or i didn't do something and I need some assistance. You see, If I run sendmail in port 25, i can telnet localhost 25 fine. but if I telnet the machine from another machine, the port is refuse. So i tested by running other programs (one at a time) listening to port 25, I cant connect.
So It seems that something is blocking specifically port 25 to receive incoming connections.
Can I have some assistance as to where to look for a configuration mistake? Basically something has my port 25 blocked on the same machine. BTW iptables is not running.
Cheers,
Generally speaking, "netstat -tpln" will list all listening tcp ports and the process that has them open. In your case, I'd bet that sendmail is probably only configured to listen on lo.
-Steve
Steve Rigler wrote on Mon, 20 Aug 2007 10:56:28 -0500:
In your case, I'd bet that sendmail is probably only configured to listen on lo.
That's at least the default in CentOS 5, I don't remember how CentOS 4 handled this. You have to put a variable in /etc/sysconfig/sendmail, but I don't know which one as I always compile my own sendmail.cf.
Kai
That's at least the default in CentOS 5, I don't remember how CentOS 4 handled this. You have to put a variable in /etc/sysconfig/sendmail, but I don't know which one as I always compile my own sendmail.cf.
dnl # The following causes sendmail to only listen on the IPv4 loopback address dnl # 127.0.0.1 and not on any other network devices. Remove the loopback dnl # address restriction to accept email from the internet or intranet. dnl # DAEMON_OPTIONS(`Port=smtp,Addr=127.0.0.1, Name=MTA')dnl dnl #
Tom Brown wrote on Mon, 20 Aug 2007 17:39:54 +0100:
DAEMON_OPTIONS(`Port=smtp,Addr=127.0.0.1, Name=MTA')dnl
This is what you have to remove from the mc file, yes. That is what *I* do. But I think it can be made easier for the average user. At least from older SuSE systems I know that this can be done with a variable in /etc/sysconfig/sendmail and then rerunning SuSE-config which will update the sendmail.cf. I would expect that something similar can be done on RHEL/CentOS.
Kai
Kai Schaetzl spake the following on 8/20/2007 11:31 AM:
Tom Brown wrote on Mon, 20 Aug 2007 17:39:54 +0100:
DAEMON_OPTIONS(`Port=smtp,Addr=127.0.0.1, Name=MTA')dnl
This is what you have to remove from the mc file, yes. That is what *I* do. But I think it can be made easier for the average user. At least from older SuSE systems I know that this can be done with a variable in /etc/sysconfig/sendmail and then rerunning SuSE-config which will update the sendmail.cf. I would expect that something similar can be done on RHEL/CentOS.
Kai
Not as far as I recall. In RedHat based distros you need to edit sendmail.mc and remake the cf file. Editing the mc is also a good thing to do to fix up some of the liberal defaults in that file, maybe following some of the guidelines in http://technoids.org/dossed.html.
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Erick Perez -
Kai Schaetzl -
Scott Silva -
Steve Rigler -
Tom Brown