On linux, ncat nor nc works with 'nb browse -g', but socat does

[boldandbusted]

So, I have a workaround for my problem, but I'd like to get to the root of the problem here, and maybe help others.

On Gentoo Linux, I have 'nc' and 'ncat'. When I run:

nb browse -g

nb responds like so:

$ nb browse -g
Listening: http://localhost:6789
Press any key to exit...ATTENTION: default value of option mesa_glthread overridden by environment.

My default browser, Firefox, launches. But fails with an error:

Unable to connect

Firefox can’t establish a connection to the server at localhost:6789.

I look with netstat -lnp, and I don't see anything listening on network port 6789 at all.

I tried to strace the issue, with strace -f -yy -v -o /dev/shm/nb.out nb browse -g, but I don't see anything obvious (both nc and ncat are in the $PATH, and found). But, 'pstree -la' shows zero subprocesses of nb. I'd expect to see nc or ncat, right?

So, I forced nb to use socat (after I installed it):

NB_BROWSE_SERVER_TOOL="socat" nb browse -g

(I had also tried to force nc (from the 'net-analyzer/nmap-7.95' package), and netcat (from the 'net-analyzer/openbsd-netcat-1.219_p1' ebuild), and saw the same behavior for both.)

And I get a nice browser view of my nb home notebook using socat. :)

I tried adding --debug to nb, but the output is silent after Listening.... Does nb have an even more verbose mode I can try? :)

I also see that there is a different netcat ebuild available 'net-analyzer/netcat-110.20180111-r2' from "https://nc110.sourceforge.io/". Perhaps that's the one that nb actually expects to see? (I'll try that later today.)

Cheers, and thanks for nb! 💯