General discussion

Locked

mail relay

By jaboy78 ·
i got a mail relay server, let say domain @testing.com

this few days, i kept on receiving unknown mail (email not yet created on my e-mail server such as werew@testing.com, gflkj@testing.com) from unknown mail address..such as weerrerter@hotmail.com, dffgfdr@hotmail.com,ersfsdf@hotmail.com...etc. so my email-relay will reply to fgghdfg@hotmail.com which is an unknown mail (maildaemon)

One day can say more than 10,000 this type of mail that floods my email server.. and i cant track is from who??

How to control or to block this spam mail??

This conversation is currently closed to new comments.

7 total posts (Page 1 of 1)  
| Thread display: Collapse - | Expand +

All Comments

Collapse -

by Deadly Ernest In reply to mail relay

Cant give specific instructions as it will vary with the mail software you are using, but essentially what you need to do is tighten up the security on the server before you get hit for sending SPAM. the mail server is allowing ANYONE to use your server as a relay to send mail.

You most probably have a wide open gateway and closing that should resolve a lot of this. But you should also tighten up your mail server.

Most mail servers are set to only accept mail from approved clients identified by their host name, IP address or domain name. When setting up a server to service your network and relay from your ISP it is usually set up behind a gateway of some sort. But it is also set up to not accept any traffic initiated from outside the network, it will get mail from the ISP by regularly contacting the ISP and asking for mail. It should only accept mail for out going from an internal mail address coming from the right host through the right connection.

Collapse -

by jaboy78 In reply to

Poster rated this answer.

Collapse -

by Choppit In reply to mail relay

If your mail server will allow, restrict relaying to trusted addresses only. If this isn't an option, either use a different mail server, or install an SMTP proxy to do this for you. Unless you get this under control, you may find your company on one of the Open Relay blacklists which are increasingly being used to block spam.

Collapse -

by jaboy78 In reply to

Poster rated this answer.

Collapse -

by shmaltz In reply to mail relay

You title this question a mail relay issue. In the description however you are describing spam and not relaying. What is happening in your case is spoofed emails (this senders have a SMTP host and configure it to say that they are sending from ???@hotmail.com, when in fact it is coming from a different machine. Besides for draining your resources there is usualy no problem involved in that. The only other problem you might have is if you have your SMTP server configured to forward every email that is unknown to a certain mailbox, than that mailbox might become very big, Since Exchange regular version has a limitation of 16GB per store it will crash your store if you reach the limit becuase of that. There is a few ways things you can do to fight this automatically.
1. Require Reverse DNS lookup for an SMTP connection to be accepted.
2. Disable the option of a public mailbox where all the emails that don't belong to a name arrive.
3. If you didn't follow 2 and you have Exchange, you can setup a Mailbox Recipient Policy that will delete massges based on the critira that you provide. That way you can make sure that Exchange will not crash because of the 16GB limitation.
Again all of the above is said if your problem is the spam and not the relaying.

Collapse -

by jaboy78 In reply to

Poster rated this answer.

Collapse -

by jaboy78 In reply to mail relay

This question was closed by the author

Back to Windows Forum
7 total posts (Page 1 of 1)  

Related Discussions

Related Forums