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

Unanswered Question
Apr 9th, 2010
User Badges:

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

  • 1
  • 2
  • 3
  • 4
  • 5
Overall Rating: 0 (0 ratings)
Loading.
Jennifer Halim Sat, 04/10/2010 - 00:06
User Badges:
  • Cisco Employee,

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 Sat, 04/10/2010 - 00:11
User Badges:

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 Sat, 04/10/2010 - 00:16
User Badges:
  • Cisco Employee,

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 Sat, 04/10/2010 - 00:24
User Badges:

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 Sat, 04/10/2010 - 03:11
User Badges:
  • Super Gold, 25000 points or more
  • Hall of Fame,

    Founding Member

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.

Actions

This Discussion