Finding your dynamic external IP

[Bob Hall]

On Mon, Aug 04, 2003 at 12:21:59AM -0400, Lowell Gilbert wrote:
> "Bob Hall" <rjhjr at cox.net> writes:
> 
> > On Sun, Aug 03, 2003 at 11:02:19PM -0400, Lowell Gilbert wrote:
> > > "David S. Jackson" <deepbsd at earthlink.net> writes:
> > > 
> > > > If your external IP number changes, as with DHCP, is there a way
> > > > to find out what it currently is?  I was thinking you could keep
> > > > BitchX logged into a chat channel and script a /dns yournick and
> > > > email yourself the results from time to time.   
> > > > 
> > > > How would you do it?
> > > 
> > > For DHCP specifically, the best thing to do is to use the
> > > dhclient-exit-hooks script to do whatever you want.  My particular
> > > example is attached...
> > 
> > I use
> > 	ifconfig rl0 | grep "inet " | awk '{print $2}'
> > where rl0 is my external interface. 
> 
> And how do you decide when to run that?  

My ISP isn't going to change my IP address while I'm using it, so 
as long as my dhclient is doing its job and renewing the lease in a
timely manner, the IP number won't change. For an always-on connection, 
I run it when I boot the gateway box. When I was using a dial-up 
connection regularly, I had a script that grepped the output from 
netstat to get IP addresses. Obviously, I ran that when I dialed up.

Bob Hall