Multiple IP addresses on an interface

L3 Networker

Multiple IP addresses on an interface

I know that I can add a second IP to my outside interface by using a /32 instead of /24 like the first one has.  My question comes in with routing.  My default route shows a going out ethernet1/1.  Since this interface has 2 IPs what IP does it use for the routing?  Will it use the one with a /24 or /32.

L5 Sessionator

Re: Multiple IP addresses on an interface


For routing ... none of them, your interface addresse will never appear in the routing stuff.

For NAT, depend wich IP you have selected in the Policy NAT rule.

"Normally" (don't like this word) you don't need to configure multiple IP adress on your outside interface, if you've got a router connected on it, with gratuitous arp, all your traffic should be redirected to your outside fw interface.

Exept if second IP will be used for:

     GP portal / Gateway

     IP for nating



L3 Networker

Re: Multiple IP addresses on an interface

The second IP will be used for a second GP Portal, so I believe it is needed.  For NAT I am using something complete different in my range rather than eth1/1's IP.

L6 Presenter

Re: Multiple IP addresses on an interface

alternatively you can add your each /32 ip address as untagged subinterface option.You can then use any for GP, and also you can use different management profile for each.

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