Traffic sharing b/w two ISP'S

ntmanjunath · ‎07-21-2008

Hi,

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.

lee.reade · ‎07-21-2008

Hi,

You can only achieve this will policy-based routing.

http://www.cisco.com/en/US/tech/tk365/technologies_tech_note09186a008009481d.shtml

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;

http://www.cisco.com/en/US/docs/ios/iproute/configuration/guide/irp_prb_mult_track_ps6350_TSD_Products_Configuration_Guide_Chapter.html

HTH

LR

michaelchoo · ‎07-22-2008

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. :-)