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BGP-Problem with SMTP Mail

lawrencejl921
Level 1
Level 1
I have 3 Cisco 3845 Border routers running BGP.  I have a
separate ISP for each Router.  I am nat'ing on each router for our mail server on port
443.  When I peer the 3 routers together I start getting smtp errors from our mail server
and users from the outside cannot get their email from Exchange server.  To keep mail working I have put a
local preference of 500 for BGP on the first border router that makes it the preferred route.  This is also the
original router with original ISP.

We have updated the MX DNS entries for our mail server to include the following entries for
our mail server.  I replaced the real domain name and IP address.

Type      Domain Name       IP Address        TTL
A      mail.name.com    1.1.1.1           2 hrs
A      mail.name.com    2.2.2.2           2 hrs
A       mail.name.com    3.3.3.3           2 hrs

Can you let me know what I am missing in order to keep my mail server working or if you
need to see my BGP configurations.     
1 Reply 1

Francis Garcia
Level 1
Level 1

It would be great if you can provide some map of the network and configurations, It would be less complicated to troubleshoot. SMTP related issues can be from a bad default gateway defined in the server, routing missconfigutations, MTU etc

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