seeking advice on the use of secondary ip addresses

[bangkydotnet]

Hi guys,

I would like to seek advice on the concept of specifying a secondary IP address for an interface.

I've been reading up at the documentation page but I'm still quite confused.

The idea I'm getting is that instead of splitting the network into multiple vlan, instead separate addressing schemes are used within the same vlan and the default gateway for each of the networks is a secondary IP adddress.

Is the concept similar to that of subinterfaces? Or is it a different thing altogether?

Please enlighten me. Thanks in advance.

[amit-singh · Accepted solution]

Hi,

Secondry Ip addresses are used in case if the primary ip address range is exhausted on the interface. If you have only one interface on to the router and wants to have more hosts then you can assign a secondry ip address on the router's interface.

It is different then using the vlan for the network segmentation. It is not similar to the sub-interfaces concept on the router. Benefits of using sub-interfaces:

1. Both layer2/L3 segmentation and security.

2. Total control over the routing.

3. QOS can be set on the sub-interfaces.

4. PBR can also be configured

5. DHCP works prefrectly on the sub-interfaces than the secondry ip addresses.

HTH, Please rate if it does.

-amit singh

[ace-cco · Accepted solution]

Hi

please be aware that quite a few routing or other concepts/features only work with a single or the first ip address on a interface. It's a band-aid - maybe a temporary solution. Readdress or redisign the subnets if possible ...

Regards

Robert