William Case wrote:
I need some help understanding how network or TCP ports work.
I am particularly confused by the concept that something is "listening"
on certain ports. I hope there isn't a little guy in my computer with
big ears, because he is probably dead by now. I haven't been feeding
Here is what I think I understand from various manuals.
If someone wants to send me an email, their 'sendmail' calls on various
functions?? from a library?? that adds an IP and a TCP header that
It helps when you realize that TCP is really a "transportation" and mail
is at another layer.
You Send an email.
Send mail goes out on the net. and finds out what system has the MX
duties for your domain (Rogers.com in this case)
It then starts a TCP connection, and goes thru the SMTP "ritual" to say
that it wants to send an e-mail. The SMTP server records the mail as it
is received, and perhaps forwards it to the mail spool where it will
wait for you to also make an TCP connection and retrieve it to your
Charles MacDonald cmacd [ at ] TelecomOttawa [ dot ] net Stittsville Ontario
1800+ Canadians oppose Bill C-60 which protects antiquated Recording,
Motion Picture and "software manufacturing" industries from change...