Thursday, 26 April 2012

DHCP: Easy as 123

This post is more for my own reference, but someone out there may find it useful.

Ok, so we had an old IP range at one our or site's networks, and we needed to change it to the new range, to keep it in line with the rest of the company's sites. Here's how we went about it (combined with things I'd do differently given the power of hindsight).

Step 1:
Get the MAC (or Hardware) addresses of network printers and multifunction copiers. I did this by browsing to the old IP address of each device and finding the MAC address in the web interface. Also make sure IP Configuration Method is set to DHCP.
Log onto to the site's server and set DHCP reservations for each device.
Step 2:
Send out at email to the site, advising of the change over and that they will need to turn their PCs and printing devices off and back on again if they experience any network related issues.
Now the next step assumes we have already configured the switches on site with 2 VLANs. VLAN 1 is the new IP range, while VLAN 2 is the old range. At this site we are using Cisco SFE2000P 24-port 10/100 Ethernet Switches.
Step 3:
This next step should be done after hours. Browse to the IP address of the switch and login. For each interface (port) change to PVID from 2 to 1. This then untagged each Port against PVID 1. In PVID 2 I then had to manually exclude each Port from VLAN 2.

Step 4:
Now the next business day all network devices should have an IP address on the new range, as long as they have turned their devices off then back on.
This was not the case for our printers and multifunction devices. As I forgot to check that the printers were set to DHCP. It turned most of them were set to a manual IP address on the old range. So I had to call users and step them through setting their printers and multi functions to DHCP IP configuration method. Before calling them, I also manually changed the DNS entries for each device to their new IP addresses on the site server. Once the devices were rebooted, they then got their new IP addresses. Hind site is a wonderful thing indeed.

No comments:

Post a Comment