Need Allowing SMTP traffic from my network only BLOCK outside network to used SMTP.

csawest.dc · ‎04-09-2010

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.

Any help would be great!

Thanks,

Vaib...

Allowing SMTP traffic from on a few IP ranges

Jennifer Halim · ‎04-10-2010

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.

csawest.dc · ‎04-10-2010

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...

Jennifer Halim · ‎04-10-2010

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.

csawest.dc · ‎04-10-2010

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...

paolo bevilacqua · ‎04-10-2010

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.