----- Original Message ----- From: "Pong" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Wednesday, March 20, 2002 5:48 PM Subject: Re: [plug] SMTP Ports Question
> > > On Wed, 20 Mar 2002, Joon Guillen wrote: > > > Does the SMTP service use the same port (25) to connect and forward the > > outgoing e-mails to its designated mail servers or do they use the ports > > above 1023? And, will the remote mail server need to respond to it (as an > > acknowledgement, or maybe something else)? > > > > when connecting to remote mail servers, the destination port will always > be 25 (SMTP standard). while source port will always be above 1023 for > qmail running as a non-root process. i would like to add to this..... root or non-root, it will usually use the *ephemeral* ports (short-lived ports usually in the range from 1024 to 5000) as source port here's the flow guillen in order for you to understand. sending email from client to server Client[IP:tcp ephemeral ports] --> Server[IP:tcp 25] relaying email from server to another smtp server localServer[IP:tcp ephemeral ports] --> remoteServer[IP:tcp 25] fooler. _ Philippine Linux Users Group. Web site and archives at http://plug.linux.org.ph To leave: send "unsubscribe" in the body to [EMAIL PROTECTED] To subscribe to the Linux Newbies' List: send "subscribe" in the body to [EMAIL PROTECTED]
