topic Re: Multiple IP's on a single interface in General Topics

Multiple IP's on a single interface

jonkuzma — Wed, 04 May 2016 19:31:50 GMT

This may seem like a silly question but hope someone will be able to answer for clarification. I have inherited a less then stellar network IP Scheme where the second octet is the same as the vlan id. However they started this in the 172. address space so I have things such as 172.111.0.0/16 as a adress range with multiple devices all assigned with static IP's. So my question is can I set a secondary IP address on the same interface currently serving these devices. So that they will continue referencing the gateway of 172.111.0.254 then also have an address of 172.17.0.254 as the new gateway so that as I'm moving things over there will be minimal interference and downtime.

Re: Multiple IP's on a single interface

BenjAudy.MTL — Wed, 04 May 2016 20:17:56 GMT

Hi,

You can put a secondary address on an interface, but make sure you enter the second address without a netmask. You will then have to add a static entry in the corresponding router. Keep in mind that both addresses will be in the same zone (that's probably you wanted anyway).

Benjamin

Re: Multiple IP's on a single interface

santonic — Thu, 05 May 2016 07:19:40 GMT

Yes you can put multiple IP addresses. Just make sure netowrks don't overlap: (hosts can overlap with networks)

So you can have like 192.168.0.100/24, 192.168.0.200/32, 192.168.0.201/32, 10.10.10.100/24, 10.10.10.150/32...

Re: Multiple IP's on a single interface

reaper — Mon, 09 May 2016 09:29:54 GMT

the secondary IP with /32 is only required if the secondary IP address is inside the primary's subnet

it's perfectly possible to have 2 subnets side by side, as long as there is no overlap: 172.111.0.0/24 and 172.16.0.0/24