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Network Address scheme change - checklist?

I have the arduous task of changing the IP address space within a 24/7 production environment now. The new address space is not within same subnet as is being used currently.

100+ L2 switches, 2 x WAN routers, Core 6509 L3 switch, 800+ hosts, printers, etc.

Is there a good checklist to follow for successful planning and execution?

Setting up secondary IP addresses on sub-interfaces on switches in order to accomplish this with AS LITTLE IMPACT as possible is already in the works.

Any other task checklists, ideas are appreciated.


Re: Network Address scheme change - checklist?

Hi Tsrader,

i would prefer to go in for a complete VLAN setup as u have got more than 800 hosts. initially, i would ask you to setup 2 diff. vlans.

one vlan will be on your existing subnet(with 800 pc's) & other one will be the new subnet(10 plus), then once if you feel comfort, then with a less down time in the night, u can make few of the pc's on a different vlans as per the departments you have.

finally your network will have diff, vlans like....

marketig vlan2

sales vlan3

accounts vlan4 & so on

since it is big network, to make comfort, i would initially setup for 10 computers on different subnet as mentioned above.

hope you understand.

rate this post.


Re: Network Address scheme change - checklist?

In addition to Anand's comments...

Generic re-addressing things to look at for potential impacts:

** if you're using it, IOS IP helper addressing for DHCP relaying, etc.

** static routes anywhere (e.g. firewalls, other edges)

** any kind of ACL, route maps, or other filtering in routers, switches, or firewalls

** NAT - e.g. NAT inbound to services

** DHCP server scopes

** DHCP params e.g. default gateway, netmask, etc.

** SLP DA's or other SLP-related infrastructure

** DNS or hosts files

** WINS server(s)

** any servers that have hard to change IP's like NetWare 5.x, 6.0

** anything that uses NDS, eDirectory, Active Directory that stores IP addresses in object attributes (e.g. servers, workstations)

** any AS/400's or mainframes, where touching the LAN interface could potentially kill all open emulator sessions

** any SQL or Intranet/web internally developed stuff where the developer was lazy and hardcoded the IP address instead of using DNS...

** any devices that do LPR/LPD to your printers

** any servers or PCs that participate in routing via RIP (e.g. Windows servers) or that would have static routes defined for some reason

** any SMTP servers that are hardcoded to use IP addresses for relaying and forwarding (to avoid DNS lookup overhead and need to rely on DNS for mail).

** any additional protocols like IPX, APPN, etc. that need to continue to work