Change of IP for Servers

[Hari]

hi! Everyone,

My name is Hari . Someone Pl help me resolve the below issue ASAP.I
wasn't sure which group would be best to post this. Iam sorry if it's
inappropriate for some of these groups.

We have 3 HP servers running windows server 2003 R2 since 4 months at
our office,
.. 1.Domain Controller (Sgp001 - 192.168.1.10)

2.Exchange 2003 Server (Sgp002 - 192.168.1.11)

3.File Server (Sgp003 - 192.168.1.12)

The servers are assigned static IP's. The IP range Iam using is
192.168.1.x.

We have an ISP who is providing internet and VPN access. We use I-pass
(dialup) to connect to internet and use Net-screen from Juniper networks for
VPN connectivity. When we do VPN thru I-pass (dialup) everything is OK and
users are able to access their Emails. But when users try VPN thru broadband
from their residence or other places where the internal IP range is similar
to the office 192.168.1.x then we are facing a problem.

The Net-screen software says 'successfully connected' but nothing happens
and users are not able to access email and the file server at the office.

When I put this issue in front of the ISP - he says I have to change the
internal IP range to something unique because since the home and office
networks have the same IP range - VPN doesn't work. I tested VPN from my
residence by changing my home router IP to 192.168.1.x - it did not work, I
then changed it back to 192.168.2.1 and I could access my file and email
server and retrieve Emails. So I decided on a range (10.73.83.x) which I
feel is unique.

I now need to change the internal IP address for my office. I have never
done this before to any network, I don't know how the servers would react to
this change. They are new HP servers which have been running since 4 months
now.

Can you please assist me on how to go about this change? What are the
precautionery steps I need to take ? If you require any further info, Pl let
me know, as I need to resolve this issue ASAP and get VPN thru broadband
available to users soon.

Thanks & Regards

Hari

 

[Kurt]

The servers won't care about the IP address changes. Just be sure you
account for all workstations, printers, routers, etc as well as the servers.
If you're not using DHCP, this might be a good time to set that up. It'll
make similar changes musch easier in the future if you can limit the static
IPs to a few servers and printers. How many home users do you have? Maybe it
would be easire to just change their internal IP addresses.

....kurt

 

[Hari]

Hi, Mr. Kurt,
Thank you for the reply. The DHCP is already set up long time back. There
are around 30 home users - and 29 of their home network is the same I Prange
+ but these people do a lot of travelling and they often found their VPN
not working because the other places happen to have the same IP range sa our
office. So I decided to change the range. My concern is how the DNS will
behave when I change the IP range ? What precautions should I take and how
to go about it? Does the change of IP has a specific procedure to follow ??

Many thanks
Hari
Singapore

 

[Kurt]

The only concerns are that everything be modified to point to the new
addresses. Static device like printers will need to have their gateway's
changed if your network is routed or if you use web printing. All servers
will need their IP Address, DNS and Gateway settings changed. In DHCP
settings, you'll have to change the scope options for the same. Everyone
will have to reboot or do an ipconfig /release - ipconfig /renew to get the
new settings. Port forwarding on routers, router interface configurations,
etc will all have to be addressed.

....kurt