The Usual Tech Ramblings

Moving Your RAS Server

Due to some unforeseen issues, we had to move our RAS server into a new DHCP scope, and VLAN today. This is usually relatively easy…

  • Change Server IP
  • Change switch port VLANs
  • Change firewall to point to new server

This went smoothly, all being completed in about 2 minutes. But on checking the DHCP scope, the RAS server wasn’t requesting any IP addresses. I recycled the RAS service, but that didn’t seem to help, only hint of an issue for RAS was the generic message about DHCP server not being reachable…

Unable to contact a DHCP server. The Automatic Private IP Address will be assigned to dial-in clients. Clients may be unable to access resources on the network.

Apparently my brain has been on overdrive, and I forgot that moving the server to a different VLAN also made the DHCP requests not reach it. This is easily resolved with a few commands on our switches…

# config t
(config)# int vlan77
(config-if)# ip helper-address
(config-if)# exit
(config)# exit
# write

A quick restart of the RAS service, and the new VLAN is hosting its assigned IP scope.