How do I increase the size of HTTP request header in my Azure App Service (Linux)

Question

I need to Post a header that is slightly larger than 8k, and from what I've researched I can increase this by modifying the value of these fields: LimitRequestFieldSize & LimitRequestLine somewhere on my Apache Server.

The problem is I have a Linux Web App Service (PaaS) setup in Azure, and I don't know where or how to change these values in Azure.

Is it possible to do this if I have an Web App Service? If so, could someone help me out?

Many Thanks, Kahl

Answer 1

This appears to be harded coded on the azure servers and isn't possible to modify.

Answer 2

I will answer in case others have this issue. There are a couple of senarious you could face on the Linux App Service:

If you using a gateway for your app service there are hard-coded limits, currently 32kb total, and 8kb field limits that cannot be changed.

If you have enabled "Client certificate mode" in the Configuration area, similar limits are in place.

If neither of these is the case, then set the header limits in the server you are using. For Apache, you create a custom startup script and specify LimitRequestFieldSize.