Search found 15 matches

by sgb
Tue Mar 14, 2006 9:54 am
Forum: Administrators
Topic: How can I prevent my server from crashing in a DOS attack??
Replies: 12
Views: 2109

How can I prevent my server from crashing in a DOS attack??

Ok, that might be the problem, is there any reason why the server ignores the ip address it came from in the first place though, like the one below? Mar 14 09:48:30 mi6 amavis[30286]: (30286-01-3) Blocked SPAM, LOCAL [192.168.1.1] [24.67.144.148] -> ,,, Message-ID: , mail_id: QREQSMVgs75y, Hits: 52....
by sgb
Mon Mar 13, 2006 4:50 pm
Forum: Administrators
Topic: How can I prevent my server from crashing in a DOS attack??
Replies: 12
Views: 2109

How can I prevent my server from crashing in a DOS attack??

Postfix does not recognize these addresses as local addresses, that is, they are not icluded in the my network parameter. See below, the 192.168.1.1 address is my firewall passing emails to my email server which is 192.168.1.10 and the other addresses are the remote addresses, none of the remote add...
by sgb
Mon Mar 13, 2006 9:27 am
Forum: Administrators
Topic: How can I prevent my server from crashing in a DOS attack??
Replies: 12
Views: 2109

How can I prevent my server from crashing in a DOS attack??

Yes, it should be receiving the message with the remote ip address.
by sgb
Fri Mar 10, 2006 1:27 pm
Forum: Administrators
Topic: How can I prevent my server from crashing in a DOS attack??
Replies: 12
Views: 2109

How can I prevent my server from crashing in a DOS attack??

The firewall is simply Nating port 25 to the internal email server which is the zimbra server.
This is the traffic pattern (incoming)

>yahoo.com:25> external firewall nic>NAT >zimbra(internal ip)
Thanks
by sgb
Fri Mar 10, 2006 8:41 am
Forum: Administrators
Topic: How can I prevent my server from crashing in a DOS attack??
Replies: 12
Views: 2109

How can I prevent my server from crashing in a DOS attack??

I have a linux firewall in front of my email server forwarding all the traffic to my email server. One of my thoughts was that since the firewall is reciving all incoming email and forwarding to the email server in the process the email server recives it as all email is comming from the internal ip ...
by sgb
Thu Mar 09, 2006 6:12 pm
Forum: Administrators
Topic: How can I prevent my server from crashing in a DOS attack??
Replies: 12
Views: 2109

How can I prevent my server from crashing in a DOS attack??

Hello, I was getting thousands of emails from another server attempting to relay these messages. As it was explained to me in the post below the zimbra email digests email in postfix>amavis>postfix>mailbox order. http://www.zimbra.com/forums/showthread.php?t=2020 The 10000 emails trying to be relaye...
by sgb
Tue Mar 07, 2006 1:30 pm
Forum: Administrators
Topic: Is my server being used to forward spam?
Replies: 11
Views: 1849

Is my server being used to forward spam?

Here's a few lines from my log, the 192.168.1.1 is my internal ip address for my firewall 192.168.1.10 is my internal ip address for my email server. 209.154.12.10 is my external interface for our email server. My server just crashed again, is there anything I can do in the mean while to prevent it ...
by sgb
Tue Mar 07, 2006 1:07 pm
Forum: Administrators
Topic: Is my server being used to forward spam?
Replies: 11
Views: 1849

Is my server being used to forward spam?

Where can I find the logs for Postfix??

I've looked in the /opt/zimbra/log directory

also in my /var/logs directory and the only thing I can find there is what I posted above. :confused:
by sgb
Tue Mar 07, 2006 12:17 pm
Forum: Administrators
Topic: Is my server being used to forward spam?
Replies: 11
Views: 1849

Is my server being used to forward spam?

Thanks for your help, I did the second test and the server passed, which the site said it means it is not relaying emails. But why am I only seeing my firewall ip address if that's the case? Would changing the zimbra user password have any effect on the functionality of the server? I see sessions be...
by sgb
Tue Mar 07, 2006 10:20 am
Forum: Administrators
Topic: Is my server being used to forward spam?
Replies: 11
Views: 1849

Is my server being used to forward spam?

Is there any way that I can stop this? like only allowing the local server to send out email?? my windows servers are running fine and they have antivirus scanners and the latest virus definitions... I'm running an scan manually but has found nothing so far. All the emails I'm seeing are coming from...