Hi I know there are a few questions on this already, but it seems my case is a little different.
Last night I upgrade to v2.479.2 of Jenkins. After the restart we got the little warning in the management section about the reverse proxy being misconfigured – even though I changed nothing about it.
It appears that your reverse proxy set up is broken.
Other than the warning this did cause a tangible issue where when you build a job (or build with parameters) it redirects you back to that incorrect url (mypublicDomain:8888, rather than mypublicDomain).
So I had a read around and found about that the little proxy test endpoint they have (see here).
It reported this
https://mypublicDomain:8888/manage vs. https://mypublicdomain/manage/
Now thats almost right… the actual Jenkins service is hosted under localhost:8888, and then IIS acts as a reverse proxy granting access via https://mypublicDomain, so it seems something has correctly rewritten the hostname for the response, but not removed the port.
I’ve not seen reports of any similar issues where the proxy response is almost correct.
The IIS reverse proxy doesn’t have any outbound rules… but up until now we’ve never needed any.
Does anyone know whats going on here?
2
This is only a partial answer, but it certainly helped with the actual issue we see with build/build with params redirecting to the wrong place.
Someone had already raised this issue with the Jenkins team
https://issues.jenkins.io/browse/JENKINS-73667
Its still not ‘fixed’ at the time of writing this and so far doesn’t look like the team want to give it much attention as they say that IIS reverse proxies are rare and I quote
I’m not willing to attempt to duplicate your configuration because I’m not interested in configuring an IIS reverse proxy
nice
Anyway, the original raiser did come back with this partial solution:
Check “Reverse rewrite host in response headers” in iis for ARR settings if anyone else is having this issue
Once this was set (I also restarted the IIS instance to be sure) this at least solved the build redirect issue. However Jenkins still reports the reverse proxy as misconfigured, but so far I’ve not seen any other actual problem caused.