ASA 5510, Port 25

Unanswered Question
Aug 11th, 2010

One of my user have optonline account and i have configured his outlook.  He can able to recieve email but can't send out.  I have check with ISP if they are blocking the port and they said no.

I have tried telnet... telnet 25 failed so that mean my firewall is blocking it.  Optonline also told that i can use 587 secure port for them.  Can you please advsie how can i open these ports.  Should i even open 25 port or it's security risk.  Thanks.

I have this problem too.
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Nagaraja Thanthry Wed, 08/11/2010 - 15:09


Do you have an access-list applied to your inside interface? If no, then the

port should not be blocked. If you do have an access-list, please try to add

a line allowing outbound port 25.

access-list permit tcp any any eq 25

Hope this helps.



lawsuites Wed, 08/11/2010 - 15:44

Yes I have access-list applied ro interface. Is opening port 25 is security risk?

Nagaraja Thanthry Wed, 08/11/2010 - 15:48

Well.. outgoing port 25 should not be an issue. Typically.. the ISP's block

it. But if your ISP has opened it up, then it should not be an issue for you

to open port 25 on the firewall.




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