> > You can resolve the IP of their firewall, by executing (on the postfix box): > > host 1.2.3.4 > > where 1.2.3.4 is the firewall IP. if this returns a name, say > joe.example.com, then resolve this name: > > host joe.example.com > > > but if the IP and the name never change, the results are cached and the > delay should only be noticed when the cache expires. > > one thing to do is to connect from one of your users machines using telnet: > > telnet smtp.example.org 25 > > and see if you get the banner quickly or not. (replace smtp.example.org > with the name of your postfix, that is, the name that your users > configured in their MUA). > > when doing so, sniff traffic on yor postfix box: > > tcpdump -n port 25 and host joe.example.com > > so that you see when postfix starts getting traffic. I get a very quick banner response when I telnet to port 25 and port 587 I do get different bannersfor port 25 I get:220 *********************************************
when I telnet port 587 I get: 220 mail.xxxxx.org ESMTP Postfix (Ubuntu) also port 587 seems to respond to normal smtp command but port 25 only give me errors with standard smtp command. Both ports seem to work fine to send email. As I understand it 587 is a submission port and it is best to allow all my users to send email via this port instead of port 25. It is possible that since I do have smtp port virus scanning on the machines that this could cause delays I will disable smtp port scanning and see if this helps. I am also going to be looking through my mail.logs to see if there is anything strange during the smtp time outs and delays. I am also able to resolve hostnames and if not get a nxdomain fairly quickly. thanks! _________________________________________________________________ See all the ways you can stay connected to friends and family http://www.microsoft.com/windows/windowslive/default.aspx
