Subj : Re: Email server update
To   : Finnigann
From : Digital Man
Date : Thu Aug 04 2005 05:30 pm

  Re: Re: Email server update
  By: Finnigann to Digital Man on Thu Aug 04 2005 07:48 pm

 >  DM> Did you trying telnetting to a known public SMTP server (e.g.
 >  DM> vert.synchro.net) on port 25?
 > 
 > Ah, to the heart of my problems.
 > 
 > Does a telnet client tell the recipient that it's a telnet session?

No. Well, not unless it *asks*, but the "recipient" (a mail server in this
case) isn't going to "ask". It's just going to treat the session like a plain
TCP session from another SMTP server. It doesn't know you're using a telnet
client.

 > If I telnet into a mail server, (for example) why would a mail server answer
 > telnet request.

Because it's all TCP. The mail server doesn't know any different.

 > I'll try it now and see.

Good. I'll wait...

 > Command line useage(?)
 > 
 > C:\WINDOWS\system32>TELNET /?
 > 
 > telnet [-a][-e escape char][-f log file][-l user][-t term][host [port]]
 >  -a      Attempt automatic logon. Same as -l option except uses
 >          the currently logged on user's name.
 >  -e      Escape character to enter telnet client prompt.
 >  -f      File name for client side logging
 >  -l      Specifies the user name to log in with on the remote system.
 >          Requires that the remote system support the TELNET ENVIRON option.
 >  -t      Specifies terminal type.
 >          Supported term types are vt100, vt52, ansi and vtnt only.
 >  host    Specifies the hostname or IP address of the remote computer
 >          to connect to.
 >  port    Specifies a port number or service name.
 > 
 > telnet -f logfile.txt vert.synchro.net 25
 > 
 > C:\WINDOWS\system32>telnet -f logfile.txt vert.synchro.net 25
 > Connecting To vert.synchro.net...Could not open connection to the host, on p
 > 25:
 > Connect failed

Oh, there you go. That indicates something, possibly your ISP is blocking your
outbound connections to port 25.

 > Is this whole thing telling me that MY port 25 is closed?

No. It telling you that everyone else's port 25 is closed to you because
something is blocking it.

 > Are ports two way? Maybe closed one way but open the other way.

Right.

                                                  digital man

Snapple "Real Fact" #94:
Lizards communicate by doing push-ups.

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