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Dual ISP Client connectivity Issue

I have connections to 2 ISPs terminated on a single router taking full routes.

ISP A- T3 address block xx.xx.xx.xx

ISP B- 2xT1 advertises the same block

I have set the local preference to 500 for ISP A.

I have also prepended our AS for our route advertisement going out ISP B.

This works to steer traffic to ISP A for the vast majority of networks. In some cases ISPs advertise more specific route only to ISP B. This results in a relatively small number of routes pointing to ISP B. It appears that hosts in these networks cannot access our web sites. I have a client in one such network who cannot access our web site.

I tried a static for the client IP point to ISP A with no luck. Any thoughts would be appreciated.


Re: Dual ISP Client connectivity Issue

We encountered a similiar problem and our ISP was not propagating our pre-pend correctly. You'll have to really bug them to get them to look into it (b/c ISP's never make mistakes :-)

New Member

Re: Dual ISP Client connectivity Issue


I think to use both the ISP at the same time for redundency and loadbalacing u need to get the one public ip pool from the both ISP.Then only u can get the same.

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