[lug] What's my IP?

[David Morris]

On Tue, Jan 25, 2005 at 09:17:44PM -0700, Jeff Schroeder wrote:
> In the end, this exercise is all part of an ongoing
> intra-office battle to see who can hork the other guys'
> machine the best.  My friend managed to get on the system
> when the other guy (who "fixed" ifconfig to report false
> information) was in the bathroom or something, and did a
> simple "xhost +" to enable X connections from anywhere.
> His plan was to then have some fun creating random
> background images remotely, or whatever other interesting
> stuff one can do with network access to a running X
> session.

LOL, reminds me of great days in the U-Grad lab in college
messing with the minds of freshmen by getting them to set
'xhost +' and locking the system from another user's
account.  Or setting VIM on someone's account to switch to a
DVORAK keybaord layout when the ESC key is pressed.  Though
I think my favorite is still the time we setup a system a
professor was using on an overhead projection to display a
picture of *ahem* questionable taste at random intervals. =)

> P.S. Lest anyone think I was "wasting" the collective
> brainpower of the LUG on such trivialties, the reason I
> brought it up in the forum is simply because I realized
> that without 'ifconfig' I don't know how to determine the
> IP of the local machine.  In the end, there are several
> ways, but many of them depend on (1) network access, or
> (2) certain software packages.  So I learned something
> useful, even if the end goal is a bit of workplace fun. :)

Another trick not mentioned is to run 'tcpdump -n' then ping
an IP address.  It doesn't matter what you ping, just enter
anything.  The outgoing packets will appear in tcpdump with
the IP address of the machine you are on.  This would be one
of the more difficult items to compromise on a machine. If
the machine in question *is* on a network you can run
tcpdump on another machine and ping that one from the one
you are trying to determin the IP of.  This is a foolproof
way of determining the IP address.

And for me at least, waste away...its this type of
triviality that is the entire reason I got into Linux in the
first place. =)

--David