Bug#930966: ITP: pwnat -- allows clients behind NATs to communicate

[Samuel Henrique <samueloph@debian.org>]

I have reviewed the packaging of Nilson Silva
<nilsonfsilva@hotmail.com> but it got blocked as I'm not sure this
package is a good fit for our official repos.

I could find issues on upstream's Github where people are talking
about how the method pwnat uses is outdated (upstream even wrote a
replacement, called slipstream)[0].

pwnat doesn't work with new routers (as of at least 2017), it might
not work with CGNAT, and it relies on the fact that the IP address
3.3.3.3 is unreachable (I'm not sure if a host on 3.3.3.3 would break
pwnat or not, but ISPs might be blocking this too now).

Some links for those issues:
https://github.com/samyk/pwnat/issues/18#issuecomment-703373953
https://github.com/samyk/pwnat/issues/17#issue-619482494
https://github.com/samyk/pwnat/issues/10#issuecomment-282223632

Since I didn't went all the way into the rabbit hole when doing my
analysis, I could be wrong and in fact pwnat will work in most of the
cases, if that's the case, please reply to this bug with details.

Thanks,

[0] https://github.com/samyk/slipstream

-- 
Samuel Henrique <samueloph>