Red Hat Bugzilla – Bug 53264
Sendmail refuses connections from everywhere except "localhost"
Last modified: 2005-10-31 17:00:50 EST
Description of Problem:
My machine is named "nelson.oit.unc.edu." When I run "telnet localhost 25" I get the appropriate "ESMTP" response. However when I run "telnet nelson.oit.unc.edu 25" I get a "connection refused" error message. I get the connection refused message when I try this from the local machine or from a remote machine. The only change I've made to the sendmail configuration from the default is that I've added "nelson.oit.unc.edu" and "nelson" to /etc/mail/local-host-names. I originally suspected the problem might be related to ipchains or my TCP_wrappers configuration, but that seems not to be the case. (I've tried stopping ipchains with "/etc/init.d/ipchains stop" but the problem persists.)
My /etc/hosts.allow file reads "sendmail : ALL"
my /etc/sysconfig/ipchains file reads as follows:
# Firewall configuration written by lokkit
# Manual customization of this file is not recommended.
# Note: ifup-post will punch the current nameservers through the
# firewall; such entries will *not* be listed here.
-A input -s 0/0 -d 0/0 25 -p tcp -y -j ACCEPT
-A input -s 0/0 -d 0/0 80 -p tcp -y -j ACCEPT
-A input -s 0/0 -d 0/0 22 -p tcp -y -j ACCEPT
-A input -s 0/0 -d 0/0 -i lo -j ACCEPT
-A input -p tcp -s 0/0 -d 0/0 0:1023 -y -j REJECT
-A input -p tcp -s 0/0 -d 0/0 2049 -y -j REJECT
-A input -p udp -s 0/0 -d 0/0 0:1023 -j REJECT
-A input -p udp -s 0/0 -d 0/0 2049 -j REJECT
-A input -p tcp -s 0/0 -d 0/0 6000:6009 -y -j REJECT
-A input -p tcp -s 0/0 -d 0/0 7100 -y -j REJECT
Version-Release number of selected component (if applicable):
Steps to Reproduce:
telnet nelson.oit.unc.edu 25
telnet: Unable to connect to remote host: Connection refused
220 nelson.oit.unc.edu ESMTP Sendmail 8.11.2/8.11.2; Wed, 5 Sep 2001 15:08:12 -0400
I need to have this resolved by Friday, September 7 or I will have lost all of the mail that's been sent to my address since Monday, Sept 3.
Have you made any changes to your /etc/sendmail.cf file to allow remote
connections? Red Hat by default ships sendmail to only allow connections from
localhost for security reasons. You can easily fix this by editing a line in
/etc/mail/sendmail.mc and then recreating your /etc/sendmail.cf file from that.
In /etc/mail/sendmail.mc change the following line
dnl DAEMON_OPTIONS(`Port=smtp,Addr=127.0.0.1, Name=MTA')
The part 'dnl' is the same as comment a line out. After saving the above change
m4 /etc/mail/sendmail.mc > /etc/sendmail.cf
Restart sendmail and you should be able to receive mail remotely. Reopen this
bug report if you do not have positive results.