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Feature that blocks outgoing port 25

Discussion in 'E-mail Discussions' started by eduardosilva, Jun 15, 2009.

  1. eduardosilva

    eduardosilva Registered

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    Hello,

    I noticed that my server wasnt sending mails, and I started to check the possible causes.

    I observed that there was a in the chain output from iptables blocking the destination port 25. I guess that this is part of something to avoid my server becoming a spammer, and probably this is an option that I enable and now it's not working fine.

    For keep services working, i removed this rule from iptables, but I would like to know where should I fix it.

    thanks.
     
  2. eth00

    eth00 Well-Known Member
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    Do you run a firewall script such as apf or csf?

    Do you have the default redhat/centos firewall? (did you ever disable it?)

    What datacenter are you in? There is a possibility they install a custom one on your server.

    /etc/sysconfig/iptables

    may give you some idea of what is going on and how you can fix it.
     
  3. eduardosilva

    eduardosilva Registered

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    Hello eth00, thanks for the input.

    Answering your questions:
    > I'm not running any custom firewall on this machine, just the default setup of cpanel.

    > Centos firewall is disabled

    > I'm on my own datacenter, the machines are provisioned by me.

    My firewall device is over a separated hardware.

    I think that after office hours, i will make a test and try a reboot to check if the rule will be on the firewall again.

    Those where my only rules in the chain output:

    Code:
    pkts bytes target     prot opt in     out     source               destination         
    ACCEPT     tcp  --  *      *       0.0.0.0/0            127.0.0.1           tcp dpt:25 
    REJECT     tcp  --  *      *       0.0.0.0/0            0.0.0.0/0           tcp dpt:25 reject-with icmp-port-unreachable 
    acctboth   all  --  *      *       0.0.0.0/0            0.0.0.0/0           
    
    (I removed the second line since i dont know what is it and was causing some problems)

    Thanks
     
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