Jo Rhett wrote:
10.x is (supposedly) not routable on the public internet. If you see 10.x (or other RFC-1918) traffic coming in from the world, your ISP is broken.
You don't run packet sniffers on your hosts much, do you? ;-)
If you do get a connection attempt from a non routable address on your SMTP servers external interface, you should have no way to acknowladge the connection if your own border router is configured correctly.
Since yor mail system can't acknowledge the TCP connection attempt, the external system using the unroutable address will not be able to correctly initiate a SMTP session.
So, AFA your mail system is concerned, mail transfers from an unroutable address should not occur even if packets from unroutable addresses do reach the host it runs on.
Regards /Jonas -- Jonas Eckerman, FSDB & Fruktträdet http://whatever.frukt.org/ http://www.fsdb.org/ http://www.frukt.org/
