Stop Open Relay
 

Would someone please tell me how to close the "relay"...I am getting hosed from lots of junk mails. Don't know what else to try???
I have sendmail 8.9.3 version

Sendmail can work with DNS-based blacklists. Note - any blacklisting system runs the risk of giving 'false positives' and rejecting legitimate mail.

I use <http://www.spamcop.net>

Hope this helps.

I would not keep an open relay even if it co-operates with spammer databases.
There is always a chance that a spammer not being in the database happens to send some hundred thousand letters via your relay.
Then you could easily find yourself blacklisted on the internet.

But can you distribute security certificates to your users?
If so, then you could setup your server to only allow relaying for those who have the certificate.

i may be reading wrong, but are you getting tons of spam, or are you being used as a relay to SEND tons of spam?

Try spam assasin if it is you getting the mail. If your are RELAYING the mail to other MTA's, then you should look at your hosts-allow file (or something like that)

Yes, I think that I may have mis-interpreted the original post; my advice was based on varunbihani's mail server receiving a lot of spam - not that it was configured as an 'open relay' and RELAYING as opposed to just RECEIVING. [A relay is when the server sends the mail out again to somewhere else, rather than the user having to pick their mail up from that server.]

If sendmail came as part of a distribution, I would imagine the security to be set up fairly well without having to touch anything. If, however, varunbihani has compiled Sendmail from source, it is possible that the problem is RELAYING not RECEIVING. If this really is the problem, there is information from mail-abuse.org:
<http://mail-abuse.org/tsi/ar-fix.html#sendmail_8>

var*,

if you are afraid you may have an open relay you can test it at:

http://www.abuse.net/relay.html


good luck

Lucas

Actually I want to know how do I stop relaying on my server so that no one else can send mail from my server other than my authorised users.

You did not answer my question: are you in the position to distribute security certificates to your clients?
If so, there is a greate article at this forum, showing how to setup a secure smtps server (and more):
http://www.linuxquestions.org/questi...ticle&artid=50

The greatest thing with that setup is that it uses stunnel. Once you configured stunnel correctly for one secure service, you can configure other secure services (pop3s, https, etc.) in one minute: just start a new stunnel daemon for the new service with the corresponding port pairs.