04-09-2010 11:42 PM - edited 03-04-2019 08:05 AM
Dear Experts,
I have facing very much problem of SMTP traffic , lots of unknown outside the network used my mail server SMTP port,
heavy much mail send through my mail server ( used SMTP port) from outside network.
I need it to block smtp port from outside network , only allowed from my network.
i am using Cisco 3845 router.
my Mail server IP 120.111.234.4
If I put in access lists for each range and nothing else associated with SMTP would that accomplish the task?
Allowing SMTP traffic from on a few IP ranges ( my network only BLOCK outside network need to configure my Cisco 3845 to only allow SMTP traffic from certain IP ranges to my mail server
so what i can do to solve this issue.
my network 120.111.234.0/22
221.212.142.0/24
210.212.152.0/25
So plese give me the soluction regarding the same.
04-10-2010 12:06 AM
You would need to configure your mail server to not allow mail relay through it.
Don't think you can block mail traffic from outside with an access-list, as it will block legitimate mail traffic inbound.
04-10-2010 12:11 AM
Dear Halijenn,
I already congured in my mail server ( no mail relay). but still facing the problem i need to block smtp through outside the network.
Thanks in ADV,
Vaib...
04-10-2010 12:16 AM
You would need to have Mail gateway, like Iron Port or CSC module on ASA firewall for example to be able to block those traffic. With access-list, you would be blocking legitimate mail traffic as well because access-list only looks at layer 3/4, not deep into the email itself.
04-10-2010 12:24 AM
Dear Friend,
I need to config in my router SMTP port not allowed to used of outside the network , it;s only allowed my network ips only. other ips block to used SMTP
Thanks,
Vaib...
04-10-2010 03:11 AM
Do you understand how email in the internet works ?
Are you able to configure correctly an email server ?
From your posts above, seems like the answer to both questions is "no".
In that case, I recommend you engage a reputable IT professional to help you.
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