VPN - Same IP's

[jslarose]

Hi,

Have a stupid question ...

We have a vpn at work using a cisco Pix and the network has an ip range
of 192.168.1.1, etc ... I have several users who are logging into the
vpn from home computers. Some of these computers I have had to change
the ip address range to be different then the work network range to
avoid conflict ... I would use 192.168.0.1 range

This seems to work ok so far ... have a question on the effects of
several home users logging in with the same ip address though. What
happens when several home users that have been assigned 192.168.0.1 by
their home routers all log into the vpn at the same time? Does this
create any conflicts or is this not even a factor when using vpn?

thanks,

JL

 

[Chris Priede]

Hi,

We have a vpn at work using a cisco Pix and the
network has an ip range of 192.168.1.1, etc ...

My condolences...

I have several users who are logging into the vpn
from home computers. Some of these computers I
have had to change the ip address range to be different
then the work network range to avoid conflict ...

....right. It might not be a bad idea to renumber the office now. As you
grow, getting remote users to reconfigure will become too much of a hassle
and renumbering will only get harder, too. The private address space (
http://www.faqs.org/rfcs/rfc1918.html ) is plenty wide and there is no
justification for half the planet using the same address block. Be
original.

What happens when several home users that have been
assigned 192.168.0.1 by their home routers all log into the
vpn at the same time? Does this create any conflicts or is
this not even a factor when using vpn?

It should be perfectly fine. The only address seen on your network and to
other users will be their VPN endpoint.

 

[jslarose]

thanks for the reply ...

Wasn't quite sure what it would do. What I did find out was that the
home users could not use the 192.168.1.x range ... it would allow the
vpn to connect but no traffic would actually pass. The problem was
fixed once I moved the home users onto the 192.168.0.x range. Just
wanted to make sure that if they happened to all have the same address
on their home machine that it wouldn't create an issue ... I guess it
wouldn't if it got natted to the wan of the router

Although it is a good idea, I'm not sure I want to take on renumbering
the office just yet. Thanks for the ideas ....

 

[Peter]

Wasn't quite sure what it would do. What I did find out was that the

home users could not use the 192.168.1.x range ... it would allow the
vpn to connect but no traffic would actually pass. The problem was
fixed once I moved the home users onto the 192.168.0.x range. Just
wanted to make sure that if they happened to all have the same address
on their home machine that it wouldn't create an issue ... I guess it
wouldn't if it got natted to the wan of the router

Although it is a good idea, I'm not sure I want to take on renumbering
the office just yet. Thanks for the ideas ....

No need to renumber Office network (192.168.1.x). Just continue to make sure
User's home routers are not using same network. Every VPN connection from
user's home machine will get a different IP (from a VPN pool) like
192.168.1.240, 192.168.1.241, etc. So there is no conflict.