Web Hosting Talk : Web Hosting Main Forums : Hosting Security and Technology : spam to postmaster...

[FIAHOST]

Hello,

spammers manged to get the list of all domain names hosted on one of our servers. Many websites provide such information for free.

Now, the spammers are sending spam emails to all our domains on the postmaster email postmaster@domain.com. They send tons of spam, we are very close to DOS attack. More than half of the server ressources are used just to cop with these emails!

I don't know if there is a way to prevent this, but I wanted to share this experience with you.

Thanks

[tamar]

Why don't you reject emails going to postmaster@domain.com? I know dnsreport suggests it, but I believe you get a warning if that address isn't present.

[FIAHOST]

I use exim, do you know a safe way to reject these emails server wide?

[tamar]

I can't say I do; I don't use exim. But can't you delete all postmaster@domain.com accounts and make sure that all emails to non-exisent users get rejected (not just bounced)? It might be a bit of time's work to do this since I don't know how to do it server-wide, but in the end, it is worth the trouble... and if you learn a shortcut while you're in the process, that'll be useful too.

[FIAHOST]

Thank you I will look out for this.

Ther is no way to do it account per account... the server host more than 800 domains.

[grandad]

Why not try Mailscanner it can reduce spam to the server considerably.

[tamar]

I'm not sure if this will help you, but check out the exim forums on rejecting emails:

http://www.google.com/search?hl=en&h...nown+recipient

When you do figure it out, please let us know