CHECK_HTTPv2: updates on uppercase headers

[KoMa666]

Hi everyone,

I just updated to CMK 2.4 and I still see this issue with lowercase HOST headers.
Are there any updates on implementing upper and lowercase headers?

CHECK_HTTPv2: Uppercase headers

CMK version: 2.3.0p12CRE OS version: Debian 12.6 Hi, is there a way to prevent check_httpv2 to convert headers to lowercase? I try “check_httpv2 -k ‘Host: 192.168.xxx.yyy’ --url ‘http://192.168.xxx.yyy/’ --method GET” and in tcpdump it will be converted from “Host” to “host”. I tested it with many different Headers like “Host”, “Host1”, … always the same, it gets converted into lowercase only what I verified with tcpdump. I have a stupid AirCon that needs a “Host” header with uppercase “H” …

[KoMa666]

Any update? Implementation should be quite easy. Maybe with an optional flag “–ignore-header-case”?

[marcel.arentz]

Hi @KoMa666,

as my colleague stated in the previous thread, the RFC defined the header key as case-insensitive. As we are – for maintainability reasons – dependent on the libraries provided by Rust, we currently cannot differ from this RFC as the used library/crate reqwest is not providing the option to ignore the conversion.

Anyway:

I sense that you need to specify the server to connect to independently of the requested website. The Host-Header you are sending in your example needs to be processed by the sender and not by the receiver. Please try in 2.4.0 with the following option:

./check_httpv2 --server 192.168.xxx.yyy --url http://192.168.xxx.yyy/ --method GET

You find the option in the http rule by it’s name “Connect to specific host”.

Does that solve your problem even though we are not able to change the current behavior for custom headers?

[KoMa666]

Hi @marcel.arentz ,

thanks for the reply but this won’t work. the check_httpv2 is using always lowercase headers. Regardless what I enter, even if I enter -k HOST:192.168.x.y it converts HOST or Host to “host” which is not accepted by the aircon.

And yes I know this is a bad behavior of the aircon, but also the forcing case conversion is not 100% “fine”

[marcel.arentz]

Hi @KoMa666,

I understand you cannot use -k as the option to provide the host header. I proposed to not set the host header explicitly but use the builtin functionality of the check plugin.

If this is not working, we unfortunately cannot support this use case as we’re dependent of the programming language library/crate. And the dependency is relying on the RFC convention.