El Mar 03 Feb 2004 07:57, Terry L Fritts escribi=F3: > Tuesday, February 3, 2004 you wrote: > CF> This is not good since many domains don't allways have complete A > CF> or =3D cname records for all of they sending computers (mta ou mua) > CF> ... Remember many legitimate mail can come indirectly from > CF> firewalls and =3D proxies shared by customers at isp level, and the > CF> isp don't allways add a =3D record for each domain handled by the > CF> firewall ... so you test will fail !! > > Yes, I agree with Gustavo. There are many reasons why mail would > come from an ip with no A record: proxies, firewalls, gateways, > and probably others. > > There are also reasons why a server would not have an mx record. > For one thing it might not be a mail server in the case of > firewalls and proxies. For another there is good reason to not > list a sending only smtp server as an MX if you do not want > incoming mail or if there are no mail boxes. > > > Terry Fritts >
If we can't validate a sender, anyone can setup a mail server and send em= ail=20 with a false identity (like virus does). Have you a idea to solve this ? Gustavo - To unsubscribe from this list: send the line "unsubscribe xmail" in the body of a message to [EMAIL PROTECTED] For general help: send the line "help" in the body of a message to [EMAIL PROTECTED]
