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Beginner

Policy based routing example

Hi

At present I have one central router where 2 line is connected . one of ISP (A) is connected to internet and other is connected to Branch office. Now all net realted data www, smptp, ftp are go through ISP (A).

I want to do:

Now another ISP (B) is connected my router. I want from specific IP or Proxy IP address request www through ISP 3 and rest of data smtp, ftp ,others rquest process via ISP 2. But if any of ISP line A or B is down then all data pass alive ISP and when two ISP is come back normal then data request previous condition.

I think anyone help me full fill this sceniro with the example.

thanks

Biplob

5 REPLIES 5
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hi there,

so which one is ISP A, ISP B and ISP C? and which one is ISP 1, ISP 2, and ISP 3?

this is a link of PBR whitepaper,

http://www.cisco.com/en/US/products/ps6599/products_white_paper09186a00800a4409.shtml

Highlighted
Beginner

Hi Biplob, you could use an access list to match the type of traffic that you are wanting to policy route and then a set command to point it at the next hop ISP that you want. This would work best if you were running some kind of a dynamic routing protocol because if the next hop you specify goes down the router will ignore the route map and route the packet normally.

For example:

access-list 101 permit tcp any any eq www

route-map NEXT_HOP

match ip address 101

set ip next-hop 10.1.1.1

int f0/0

ip policy route-map NEXT-HOP

You could also try using the set interface command. You could do something like:

route-map NEXT_HOP

match ip address 101

set interface serial0 serial1 serial2

The router will use the first available interface in the list.

Highlighted

Hi

I mistype .correction is regarding ISP A B C=

Hi

At present I have one central router where 2 line is connected . one of ISP (A) is connected to internet and other ISP (B) is connected to Branch office. Now all net realted data www, smptp, ftp are go through ISP (A).

I want to do:

Now another ISP (c) is connected my router. I want from specific IP or Proxy IP address request www through ISP C and rest of data smtp, ftp ,others rquest process via ISP A. But if any of ISP line A or C is down then all data pass alive ISP and when two ISP is come back normal then data request previous condition.

Highlighted

Hi IZA

Thanks your example.

in your example you shows permit all IP.

BUT if if I permit from specific IP request www through ISP C then just change the ACL.

like if my pc IP is 203.113.178.5 and next hop is 10.1.1.1

then I just edit:

access-list 101 permit tcp any 203.113.178.5 eq www

route-map NEXT_HOP

match ip address 101

set ip next-hop 10.1.1.1

Pls let me know

thanks

biplob

Highlighted

Hi Biplob, it looks like you are on the right track except that access-list would route anything destined for 203.113.178.5. I think you want anything sourced from 203.113.178.5 with a desination port of 80 don't you? That would look like this:

access-list 101 permit tcp 203.113.178.5 any eq www

Either way I think you have the right idea.