Hello Vaibhav,
I'm happy to know the eBGP setup is working. This is good news.
if you want to do this only for a few web sites you can use PBR= policy based routing.
You need to resolve with DNS the URL of interest and to create a list of ip addresses you would like to divert to the other ISP
so if web site of yahooo would be 100.200.100.22 you should divert traffic with this destination
build the list
buid an extended access-lists with lines like the following
access-list 111 permit tcp any host 100.200.200.22 eq www
this is an approximation because the web site can have multiple mirrors and also because a single web page contains content coming from different sources (think of AD banners and so on)
build a route-map
route-map WebPBR permit 10
match ip address 111
set ip next-hop ISP-ip-address
on internal interfaces you need to put
int g0/0
ip policy route-map WebPBR
as an atlernative way you could do it in BGP by using a route-map to selectively increase weight only for some prefixes
in this case you could use a prefix-list
hint: to build the route-map you need to process the list of web-sites using
sh ip bgp web-site-ip address
because you need to find out the IP prefix to which the ip address of web site belongs
so from a list of web sites ip addresses you get a list of IP prefixes.
For describing the IP prefixes you can use a prefix-list
ip prefix-list websites seq 5 permit 100.200.22.0/24
...
the route-map requires two blocks
route-map incomingISPB permit 10
match ip address prefix websites
set weight 50000
route-map incomingISPB permit 20
set weight 25000
you need to apply this inbound to neighbor ISPB
the limit is that you should review the configuration of PBR or of the route-map to keep it updated
Hope to help
Giuseppe
