ISS ARR for Exchange 2019 with different internal and external domain names

Question

Hello to everyone.

I have 1 Exchange 2019 server.

Internal domain name (inside organization perimeter) is mail.a.local

External domain name is mail.b.com

I want to set up a reverse proxy for it because i will connect several new external domains to it mail.c.com, mail.d.com etc. I mean i want to redirect external requests to sites mail.b.com, mail.c.com, mail.d.com to just one local server with internal name mail.a.local

I setuped ARR ISS according to https://techcommunity.microsoft.com/t5/exchange-team-blog/part-1-reverse-proxy-for-exchange-server-2013-using-iis-arr/ba-p/592526 but i get 502.3 and 502.4 errors when trying to connect to mail.b.com

I think the problem is with different local and external domain names, but i don't understand how to setup it right.

Please help.

Thank you in advance.

Answer 1

Hi @NTforGood

Here is a documentation which may be helpful:

Troubleshooting 502 errors in ARR

Please follow the advice in the link to check if the cause can be network issues between the ARR server and Exchange server.

Besides, do you have the required certificate installed on Exchange and the ARR server?

A similar thread: IIS 10 Reverse Proxy 502.3 - Bad Gateway Security Error

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