Re: Computer ID / IP Address Questions

Your ISP assigns the IP address to you from a group of IP addresses that
they "own". . If you use dial-up, that IP address can change each time
you make a connection. If you use cable or DSL, the IP address may be
fixed or subject to change depending on the ISP and the type of account
that you have. Some charge extra for a fixed IP address which would
allow you to run a server accessible to others on the Internet.

Every packet of data that you send and receive on the Internet has your
IP address in it. When you send you PC puts the IP address in it and
when another computer responds to you it uses the IP address to send
back to you.

The received headers are inserted by mail servers when messages pass
through them. The last (bottom most) is where the message entered the
Internet. And yes the Yahoo mail servers know your IP address.

As for the data before the IP address, in some cases, that the name
registered for the IP address. The server can do a NSLOOKUP on the IP
address to get the name.

There may also be the computer name before IP address (and before the IP
address registered name if present). When you are sending via Outlook
Express, it sends that name to the SMTP mail server. I don't know web
mail would have access to that.

--

Mike - http://pages.prodigy.net/michael_santovec/techhelp.htm


"mark4man" <mw.forman@xxxxxxxxxxx> wrote in message
news:uPrN2h6VHHA.1756@xxxxxxxxxxxxxxxxxxxxxxx
People...

When I e-mail my office computer at work, from home...If I check out
the
e-mail's properties on the Details tab...it tells me the message was
"Received From": 1) a unique ID c/o letters & numbers (e.g.,
bubba9axb7yui4bt); & 2) a 12 digit number (looking similar to
123.456.789.123). I am assuming the first is my Computer ID; & the
second my
IP Address.

If I then go to my web mail service (in this case, yahoo), send an
e-mail
back to my home computer; & check out that e-mail's properties...in
that
message source, the very last "Received From" listing also shows my
home
machine's IP address.

So...a few questions:

1) That first ID...that is in fact my Computer ID, unique to only my
machine, right?...& where do I find that ID's location/information on
my
hard drive?

2) The second number...that is in fact my IP Address, right? Is that
number
unique to my machine, or is it a number assigned by my ISP
(meaning...does
it change if I change internet service providers?)

3) How in the heck did yahoo know my web mail message originated from
my
computer? Does their e-mail utility do a search of the user's hard
drive to
locate that number in a specific file & folder...or do they get it
from the
home e-mail address one provides when they sign up?

Thanks,

mark4man




.

Relevant Pages

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