Messaging Gateway

   Hello everyone,

   I have been searching a solution for all the week, but can not get it working right yet.

   Our Brightmail 8.0.2 is accepting Internal Mail Relay.


   How i can prove it:

   From an outside IP, i make a telnet connection to my Brightmail server, than, i send an e-mail pretending to be a user from my company (fake@mycompany.com.br) sending a mail message to someone inside (real-user@mycompany.com.br).

   The e-mail goes directly to the user.


   What i have done so far:

   Spam -> Sender Authentication

  

   (The Brightmail is set to Hold Message in Spam Quarantine if caught here)

   Also, i verified that this is set too:

   Administration -> Configuration -> myserver.mydomain.com.br -> SMTP -> Advanced Settings

  
  

   But i still able to send fake sender e-mail to my users.

   Does anyone have any clue ?

   Thanks a lot !
   Carlos Oliveira

 

Hi Carlos,

Please take a look at the following KB article:

http://service1.symantec.com/SUPPORT/ent-gate.nsf/docid/2008111714541154

Regards,

Adnan

Hi Carlos,

As per your post you are saying that you tryed telneting your brightmail appliance from outside your corporate network and send a mail.

Solution.....

So it looks like that mail server or brightmail is an open relay. To block this please contact your firewall vendor to configure the same.

Hi Carlos,

You can also take a help of mxtoolbox.com to check your domain for Open relay..

   Hi folks,

   Thanks for all the help already... but just to make this point clear: my server is not an open-relay.

   Outsiders cannot send e-mail trough my server to other domains.

   This problem is just an INTERNAL open-relay, wich means that outsiders can send e-mail pretending to be a third domain to my internal users.

   Anyway, i am still searching, i am working on the page AdnanH informed, i will post results later.

   Thanks to all !
   Carlos Oliveira

You are welcome, Carlos.

I hope that KB article helps to resolve the issue.

Regards,

Adnan