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HAProxy 2.2 with Exchange 2019 - Continious password prompt


i’m a bit stuck setting up my HAProxy reverse proxe in combination with Exchange.

I have several webservers but only 1 public IP so i opted for HAProxy as reverse Proxy.

All my websites work except for the Exchange 2019 - Outlook connection.

When i fire up outlook from an external connection i continuously get prompted for a password.
Internally (or when i configure my hosts file to point to the reverse-proxy) everything works great.

I’m a bit at a loss what the problem could be.
I’ve stripped my config file to remove my public address etc. and i removed the other sites/acl’s.
Can you please take a look at my config and tell me how i f-ed up? :slight_smile:

Here is my cfg file: https://pastebin.com/Gk56CmCn

Thanks in advance for any advise :slight_smile:

What do you have for the following on your CAS?


The KeepAliveTime key is not present.

add the key, and set it for a value that is equal or less than your HA backend server timeout value.

I personally I have mine set to 30 minutes, and have my HA backend timeouts for client (front end) and server timeout (backend) set to the same
or 1800000 for decimal. unit is milliseconds

thanks for the advice.
Unfortunately: no dice :frowning:

i set the reg-key; restarted the CAS server, double checked HAproxy time-out values but still continuous password prompts :frowning:

whats your updated cfg look like?

Hi, this is my current config: https://pastebin.com/KSMaYbhe

try comment/remove all of the http-keep-alive

timeout http-keep-alive
option timeout http-keep-alive

i don’t get it…the password pop-ups keep coming back.

ntlm should be proxied correctly…

perhaps it an issue with your stickiness. what happens if you only configure a single backend without the cookie/stickiness etc…