IP Migration to different Class of network

[biaman]

Newbie

I'm trying to move our network from a 10.128.0.0 (255.255.0.0) network range to a 172.26.1.0 (255.255.255.0)range. We have a mixture of DHCP and fixed addresses.
But I cannot migrate all at once due to the nature of some server applications running.

Can anyone give me some guidance?

 

[markdmac]

Boy are you in for a headache.

You have a lot of things to consider. First off, there is no way to specify which DHCP Server your clients will respond to, so once you switch over the scope all of your machines could start getting those addresses.

Your best bet is probably going to be to identify all of your machines IP addresses & mac addresses and give them all static IPs while you convert to the new subnet. That way you can control which machines get the new addresses. You should not need to visit each machine as you can use vbscript to do the configuration remotely and in mass.

Watch out for legacy printers in addition to your applications. They often have trouble with switching, especially older copier/printers.

I hope you find this post helpful. Please let me know if it was.

Regards,

Mark

 

[baddos]

If you had a firewall or router laying around you could connect the two networks together and use NAT to translate your 10.128.0.0 network to 172.26.1.0 network...


You just need to be careful since you are moving from a larger /16 to a smaller /24 which leaves you with less available host addresses to use.

 

[markdmac]

baddos, But how could they do that with the same cable plant? If they could isolate the users to a different switch I could see using this suggestion.

I hope you find this post helpful. Please let me know if it was.

Regards,

Mark

 

[biaman]

Thanks chaps, one thought I've have, can I install another network card with a stack setup on the new class C range and somehow bind a scope to the new stack?

(please don't laugh I'm a newbie)

 

[ajrox]

1.) multihome the servers with the apps{add another network card} and set up the static IPs as needed on the second interface.
2.) set up another DHCP scope at the range you want to use.
3.) disable {dont remove} the first scope {the 255.255.0.0)
4.) activate the new scope
5.) see what happens.
if you get FUBAR, disable the new scope and activate the old scope.
if you have switches and routers in the mix between the servers and the clients, you are in for a head ache.
you might want to try this with just a few clients and a single server to see where this gets you.
be sure to research the apps you were talking about and perhaps call the mfg tech support and ask some questions.
kuddos to markdmac for the IP printer issues you might have!!
good luck
AJ

 

[baddos]

You could actually use just one router, but use secondary addresses. Then NAT one address range to the other, as long as the PC's use that router as their gateway.

You don't need two separate layer2 networks.

 

[biaman]

Thanks guys I post an update to tell you how I got on.



Regards
Ian