New network segment, VLANs and CORE HP ProCurve 5406zl

[PatricioOrtega]

Hello dear HP community,

I'm Patricio Ortega, IT Administrator at my new job and i dont have more experience than the university so I need of your experience and knowledge. please :)

So lets begin!

We have many vlans configurated in the switch CORE (HP 5406zl), recently our IP address range of the VLAN 140 192.168.140.0 /24 are over... so I need to add more IP for future devices. I thought add a new vlan with the new subnet (192.168.141.0 /24) and configure a new scope on the DHCP server to automaticaly asign IPs.
But... I read a about "Multinetting" that allow combine two or more subnets on the same VLAN.
If I apply that option, need I change some other configurations?
Is it going to work?

Cheers!

[parnassus]

Multinetting VLANs are supported (Multiple IP Addresses configured on a VLAN, that is "multinetting"): see, as reference, ArubaOS-Switch Basic Operation Guide for 16.04 (or, better, for the actual software version your 5406zl is running on...since you have an old HP ProCurve 5406zl and not a new HP ProCurve - now Aruba - 5406R zl2).

Basically you should be able to add an additional Subnet (not limited to just only one <-- up to 32 IP Addresses for the same VLAN should be supported) with steps below, supposing VLAN 140 is the actual VLAN you want multinet to apply:

5406zl(config)# vlan 140
5406zl(vlan-140)# ip address 192.168.141.254/24

#
# With above commands I suppose you already have VLAN 140 defined with the IP Address of
# 192.168.140.254/24 so the VLAN 140 currently allocates its primary Subnet on
# 192.168.140.0/24 net.
# By adding another (secondary) IP Address that belongs to 192.168.141.0/24 net
# you are multinetting the VLAN 140 as you want.
#
# Then perform a:
#

5406zl(config)# show ip

#
# to display the full IP address listing for multinetted VLANs.
#

You, eventually, can also multinetting the Default VLAN (VLAN 1) if necessary.

Clearly then you have to deal with DHCP to serve added Subnet for that specific VLAN you have multinetted (probably you need to have a sort of super-DHCP Scope into which you define two separate sub-DHCP Scopes, one dedicated to the VLAN's primary Subnet and the other for the added one...this with regard to the specific multinetted VLAN).

[PatricioOrtega]

Hey, thank you very much!, I'm going to try it option and about DHCP super scope we already have it, so just I should add the new subnet and specify in the vlan interface the ip helper-address...

Cheers!

[parnassus]

That's great Patricio.