Setting Virtual IP's

[MikeL_4]

We are using APA, along with VLAN tagging...

LinkAgg0 0x643150002018 900 UP    lan900 snap900 14  ETHER     Yes     119
VLAN5001 0x643150002018 5001 UP    lan5001 snap5001 65  ETHER     Yes     119
VLAN5000 0x643150002018 5000 UP    lan5000 snap5000 64  ETHER     Yes     119

I now need to setup Virtual IP's on these, do I issue the ifconfig on the lan900 or lan5000 to do this??

i.e.:

ifconfig lan900:1 10.195.20.xx netmask 255.255.255.x

ifconfig lan5000:1 155.90.10.xx netmask 255.255.255.x

ifconfig lan5001:1 192.168.32.xx netmask 255.255.255.x

[Matti_Kurkela · Accepted solution]

If you want your virtual IP traffic to be transferred untagged, you can create the virtual IP directly on the link aggregate (lan900:1 in your case).

But if you want your virtual IP traffic to go to one of the tagged VLANs, then you should use the appropriate VLAN interface for creating the virtual IP (lan5000:1 or lan5001:1).

A physical network interface configured for VLANs can carry up to 4094 tagged VLANs, but only one untagged VLAN. The untagged VLAN is optional: depending on your network setup, it may be useable or not.

It's also possible to run multiple separate IP segments within a single physical network segment or VLAN (if at most one of them uses DHCP), but if your network infrastructure supports VLANs, you should have no reason to do that.