03-24-2007 01:02 AM - edited 03-05-2019 03:05 PM
How can we use the secondary address in a router interface ? How does it work ? What is the command to configure the secondary address in a router interface?
03-24-2007 01:21 AM
Hi
The usage of secondry address depends upon u r requirement.i.e during IP migration etc.
u can use the below commands to configure it.
int f0/0
ip address 1.1.1.2 255.0.0.0 secondry
Thanks
Mahmood
03-24-2007 04:38 AM
Hi Manoj,
Any device you are connecting directly below Router or L3 switch you have to add primary address
Attached Image and below config will guide you.
Router
f0/0
ip address 10.0.0.1 255.255.255.252
ip address 192.168.1.1 255.255.255.0 seecondary
ip address 192.168.2.1 255.255.255.0 seecondary
ip address 192.168.3.1 255.255.255.0 seecondary
ip route 172.16.5.0 255.255.255.0 192.168.1.2
ip route 172.16.3.0 255.255.255.0 192.168.3.2
Please rate if your question is answered
Regards
S. Shantharam
03-24-2007 08:27 AM
The primary use for secondary addressing is for address migration, for example:
Your company wants to re-do their addressing, perhaps to make it more hierarchical for the purpose of proper summarization, or to expand the node count.
Both address blocks can be assigned *** TEMPORARILY *** to one interface, so that the clients can be migrated in phases and still have be be able to access all of the network resources. Once the clients are migrated, the SECONDARY addressing should be removed from the interface.
SECONDARY addressing is considered a security risk, it can screw up some routing protocols, and unnecessarily complicates the operation and administration.
SECONDARY addressing should not be used for anything other than temporary, "band aid" workarounds until the ultimate solution can be implemented.
To use it, just add an additional address command to an existing interface:
ip address 172.16.1.0 255.255.255.0 <---existing
ip address 192.168.1.0 255.255.255.0 SECONDARY <---adds additional address block
ip address 10.1.1.1 255.255.255.0 SECONDARY <-----Adds a third address block
You can have any number of additional SECONDARYs, but remember, it's not meant to be anything but a temporary solution.
Good Luck
Scott
03-24-2007 10:31 PM
Thanks, this information is very knowledgable and very useful. Thanks once again.
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