1 Topic by rubberducky

  • rubberducky
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Topic: Banned IP address for only SMTP

Using Outlook, I can only receive mail. When checking the configuration, it will let me log into POP, but not SMTP. Where do I start to troubleshoot this?

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2 Reply by ZhangHuangbin

  • ZhangHuangbin
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Re: Banned IP address for only SMTP

Sorry, i don't quite understand what your issue is.

*) What's "banned IP address"?
*) What configuration did you check? Outlook setting?

3 Reply by rubberducky

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Re: Banned IP address for only SMTP

Sorry, I do think I could have done a better when writing that post. Let me explain better than what I have.

I am running the latest version of iRedMail.
I set up an email account and test it using outlook 2007 from the local network, where I am able to send and recieve email. Then, I go to the location where the user is, set it up again, but in testing I am only able to log into pop. The attempts to log into smtp fail.
I tried it again from a third location, where it worked fine, so I am assuming the IP address of the user's location is somehow banned.
So far I've used both port number 25, and port 587, with the same results.

4 Reply by ZhangHuangbin

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Re: Banned IP address for only SMTP

I guess it's blocked in iptables, triggered by Fail2ban.
Fail2ban will invoke iptables to black your IP address if there were several password failure. Is this your situation? Please check iptables rules to see whether your ip address is blocked there. For example, command "iptables -L -n".

5 Reply by rubberducky

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Re: Banned IP address for only SMTP

The output from iptables -L -n is:

Chain INPUT (policy DROP)
target     prot opt source               destination
fail2ban-postfix  tcp  --  0.0.0.0/0            0.0.0.0/0            multiport dports 80,443,25,587,110,995,143,993,4190
fail2ban-dovecot  tcp  --  0.0.0.0/0            0.0.0.0/0            multiport dports 80,443,25,587,110,995,143,993,4190
fail2ban-roundcube  tcp  --  0.0.0.0/0            0.0.0.0/0            multiport dports 80,443,25,587,110,995,143,993,4190
fail2ban-ssh  tcp  --  0.0.0.0/0            0.0.0.0/0            tcp dpt:22
ACCEPT     all  --  0.0.0.0/0            0.0.0.0/0            state RELATED,ESTABLISHED
ACCEPT     all  --  0.0.0.0/0            0.0.0.0/0
ACCEPT     tcp  --  0.0.0.0/0            0.0.0.0/0            tcp dpt:443
ACCEPT     tcp  --  0.0.0.0/0            0.0.0.0/0            tcp dpt:25
ACCEPT     tcp  --  0.0.0.0/0            0.0.0.0/0            tcp dpt:587
ACCEPT     tcp  --  0.0.0.0/0            0.0.0.0/0            tcp dpt:995
ACCEPT     tcp  --  0.0.0.0/0            0.0.0.0/0            tcp dpt:993
ACCEPT     tcp  --  0.0.0.0/0            0.0.0.0/0            tcp dpt:22

Chain FORWARD (policy DROP)
target     prot opt source               destination

Chain OUTPUT (policy ACCEPT)
target     prot opt source               destination

Chain fail2ban-dovecot (1 references)
target     prot opt source               destination
RETURN     all  --  0.0.0.0/0            0.0.0.0/0

Chain fail2ban-postfix (1 references)
target     prot opt source               destination
RETURN     all  --  0.0.0.0/0            0.0.0.0/0

Chain fail2ban-roundcube (1 references)
target     prot opt source               destination
RETURN     all  --  0.0.0.0/0            0.0.0.0/0

Chain fail2ban-ssh (1 references)
target     prot opt source               destination
RETURN     all  --  0.0.0.0/0            0.0.0.0/0

6 Reply by ZhangHuangbin

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Re: Banned IP address for only SMTP

OK, not blocked in iptables.

rubberducky wrote:

Then, I go to the location where the user is, set it up again, but in testing I am only able to log into pop. The attempts to log into smtp fail.

Is there any restriction in the user's office? For example, restriction in the network gateway/router/etc?