Configure Multiple IP Address on a Cisco Router Interface


  1. pls let me know the model #of this cisco router


  2. Author

    Not sure if I correctly remember. But, very likely on a 2811

  3. i have got a 1841 cisco router. it have got secondary interfaces. i have tried on packet tracer with same router model “1841” but secondary is not available.

    Mustafa Gökhan Kurt
  4. I’ve configured several secondary IP addresses on my 1811, and for some reason only the primary is reachable from the internet. Any advice? They are all on the same subnet, and when doing a trace route on the secondary IPs it times out at the last hop before my router.

  5. Jon M,
    It seems like maybe the packets TTL (time to live) is expiring before it gets there. Unless someone has something else, that’s all I could think of.

  6. What are the IP and subnet assigned to the primary and secondary address. Its possible that your secondary IP doesnt have a route to the internet or it doesnt participate on the routing protocol that you use. If that is the case, you need to setup a static route for the secondary IP.

  7. Hi,

    Is it possible to Configure same IP Address in the Different interfaces on a Router.

    Thanks & Regards,
    Robinson A

  8. Hi..

    My ISP has given me details below:

    How can I enter this information on a router interface?


  9. What is the effect of having many subnets on a single router interface? Does it affect browsing speed or increase latency?

  10. Hi,

    If I use secondary IP of different subnets and in the same interface (e.g Vlan1) I use standby IP (HSRP), may I have conflict?


  11. Hi
    If you want assign the ip address,subnet Mask and default Gateway
    This is IP Address and Subnet Mask

    R1(config)#int g 0/1
    R1(config-if)#ip address

    Defautl Gateway is

    R1(config)#ip route


    R1(config)#ip default-gateway

    Secondary IP is

    R1(config)#int G 0/1
    R1(congig-if)#ip address
    R1(config-if)#ip address secondary
    R1(config-if)#ip address sedondary
    R1(config-if)#ip address secedonary
    R1(config-if)#n shutdown

    For Every Network their is a seprate gateway you need to assign,it is depend on your subnet and isp assigned Gateway.

  12. the effect is that you can have the router accessible by multiple subsets. should not change much at all.

    if u are trying to trace using the secondary i beleave you need to change the routing table to match the secondary network number. something like

    ciscorouter# conf t
    ciscorouter(config)# int fa0/1
    ciscorouter(config-if)# ip address
    ciscorouter(config-if)# ip address sec
    ciscorouter(config-if)# exit
    ciscorouter(config)# ip route

    that should forward traffic properly

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