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New Member


Hi there,

i have a problem to configure a Cisco Router 1921 because i am not knowing this very well.

i have following situtation:

We have an existing network with and a default gateway with The default GW is at the moment the Firewall.

Now we have to set up a new enviromet with a new IP Range. we have for the servers a /24 and for the Clients a Now we want to route between the networks because we can not make a big bang ip  migraten.

So we want to router between the these 3 networks and for that we want to use the 1921. If it is possible i want on the interface g0/0 all the different networks and the g0/1 will be connected directly to the Firewall. Is that possible ?


I tried a few things like bind on interface g0/0 sub interfaces with the ip address of the default gateway for the 3 different networks.

can some help to make it work

Thanks in advance





New Member

Hi Peter,Your direction is

Hi Peter,

Your direction is probably right. You have to configure sub-interface on g0/0 with differenet network. In addition, encapsulation must be defined before activitate the sub-interface. The connected port must be trunk port in advance. Then you could assign mutiple IP address on one single interface with different vlan. Examplet of configuration:

interface GigabitEthernet0/1.10
 encapsulation dot1Q 10
ip address

interface GigabitEthernet0/1.20
 encapsulation dot1Q 20
 ip address


Hope it can help you.


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