Traffic sharing b/w two ISP'S

Unanswered Question
Jul 21st, 2008


We are using two ISP A and B, I want to send the HTTP traffic via ISP A and mail SMTP traffic via ISP B. Would you please let me know the simple configuration for this concept.As per the attached fig.

I have this problem too.
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lee.reade Mon, 07/21/2008 - 23:44


You can only achieve this will policy-based routing.

You should also check out some added features to give you failover to the other isp in case of outage, as be default traffic would just get black holed;



michaelchoo Tue, 07/22/2008 - 00:10

For outbound connections, you can use policy-based routing as the previous poster suggested. If ISP B provides SMTP gateway services/relay, you can simply point your internal SMTP server to route all outbound mail traffic to ISP B's SMTP gateway (no need for policy-based routing for this)

For inbound, it's another matter. If you got allocated different blocks of IP addresses from both ISPs, it's simply: simply register your MX record using an IP address from ISP B's block of addresses.

Oh, by the way, BGP with your ISPs is a given, I reckon. Static routing will be too hard to maintain, can lead to sub-optimal routing at best and routing loops at worst. :-)


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