02-21-2008 11:43 PM - edited 03-03-2019 08:49 PM
Hi, I want to ask how to configure a failover for a default route (ip route 0.0.0.0 0.0.0.0 <gatewayIP>)
If the default route 222.222.222.222 is not reacheable, how can i automatically put a backup default route of 111.111.111.111? How can it test if the GW 222.222.222.222 is down so that it can put 111.111.111.111 as the GW.
Thanks,
Ninoy
02-21-2008 11:46 PM
Pre,
With administrative distance. i.e.
ip route 0.0.0.0 0.0.0.0 222.222.222.222
ip route 0.0.0.0 0.0.0.0 111.111.111.111 10
Once 222.222.222.222 is not reachable (shutdown the interface - or unplug the cable), 111.111.111.111 will be the GW.
Regards,
Dandy
02-21-2008 11:50 PM
Hi Dandy,
Thanks for the fast reply, but is there any way that 222.222.222.222 is not reachable on the server side of the network and the router detects that the link is still active, its just if you ping it, it will result to a timeout.
Thanks,
Ninoy
02-22-2008 04:29 AM
Hi,
Who's pinging? The server or the router?
...and what is the link type connected to the router interface for the 222.222.222.222?
Regards,
Dandy
02-22-2008 12:28 AM
hi
I do not know what real topology is there, it`s just a suggestion:
if GW 111.111.111.111 & 222.222.222.222 are in the same router, the router have a loopback interface with ip address 3.3.3.3 and have a right route to come back,
so now
ip route 0.0.0.0 0.0.0.0 3.3.3.3
ip route 3.3.3.3 255.255.255.255 111.111.111.111
ip route 3.3.3.3 255.255.255.255 222.222.222.222
regards
dongdong
02-22-2008 01:01 AM
Hi,
If I assume that you are using two different interfaces for a single gateway with two deferent bandwidth from two deferent/same ISP, then you can choose the following:
ip route 0.0.0.0 0.0.0.0 Serial0/1/1
ip route 0.0.0.0 0.0.0.0 Serial0/1/0
It'll help you to loadbalance the bandwidth as well as it will work the same if one link goes down.
or you can go as per medan's post (Senior Consultant, NCS Pte. Ltd)
Thanks
Goutam
02-22-2008 01:29 AM
hi Goutam
if peer router has a interface Serial 0/0/0 that connect to local interface Serial 0/1/1 , remove ip address from Serial 0/0/0 and remain encapsulation PPP, both side`s serial interface will still display "up up", maybe loadlance between two link is fail.
regards
dongdong
02-22-2008 02:04 AM
Hi Dong Dong liu,
I appreciate your point, but please let me know why you are going to withdraw the IP address by remaining the Encapsulation? Any valid reason to doing the same in production network? Where as, at that condition no data will flow.
See, my point of view is that to send the traffic load with the both active interface, as well as with the help of load balancing. Where I'd like to utilize the max through put of the both link at a time if 1 interface goes down then, the remain active interface will also able to carry the traffic very well.
Suggestion is always appreciable.
Thanks
Goutam
02-22-2008 02:40 AM
hi Goutam
thanks for sharing your opinion, I agree with your point of view, LB is a good idea.
I just think of local interface act as a GW, if peer interface has "a little" problem and local interface`s states is "up up",so this default route is still a valid route in the local route table, and half of the traffic will still flow that interface. It's a bit of risk.
regards
dongdong
02-22-2008 04:15 AM
Hi Dong Dong
Thanks again :)
If I configure my site-office router with the bellow congiguration:
Router-Site-Office#sh ip int brief
Interface IP-Address OK? Method Status Protocol
FastEthernet0/0 x.x.x.x1 YES NVRAM up up
Serial0/1/0 10.10.1.2 YES NVRAM up up
Serial0/1/1 20.20.1.2 YES NVRAM up up
Router-Site-Office#sh run | in ip route
ip route 0.0.0.0 0.0.0.0 Serial0/1/1
ip route 0.0.0.0 0.0.0.0 Serial0/1/0
Router-Site-Office# sh ip route
C10.10.1.1/32 is directly connected, Serial0/1/0
C10.10.1.0/30 is directly connected, Serial0/1/0
C20.20.1.1/32 is directly connected, Serial0/1/1
C20.20.1.0/30 is directly connected, Serial0/1/1
S*0.0.0.0/0 is directly connected, Serial0/1/1
is directly connected, Serial0/1/0
If HO as per bellow:
Route-HO# sh ip route ++
C10.10.1.0/30 is directly connected, Serial0/1/0
C10.10.1.2/32 is directly connected, Serial0/1/0
C20.20.1.0/30 is directly connected, Serial0/1/1
C20.20.1.2/32 is directly connected, Serial0/1/1
S*0.0.0.0/0 is directly connected, Serial0/1/1
is directly connected, Serial0/1/0
++ if no other route is connected with HO router, then go for this option.
As per the above post âhow to configure a fail over for a default route?â I think its pretty clear how to do that. The main post is related with the âfail overâ, then we can assume that there are more than one link (2 in this case). When 2 links are available, then consider the both links to use with the max utilization. See the basic point is how you are observing the network/ the topology. And as per my knowledge CISCO has given us the facility to play with data as you can. ;)
Thanks
Goutam
Find answers to your questions by entering keywords or phrases in the Search bar above. New here? Use these resources to familiarize yourself with the community: