CI: Test with libslirp 4.3.1 on CentOS 7

[mbargull]

This is a followup to #234 (comment) :

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@mbargull in #234 (comment) :

I did not investigate this further, so can't tell if it's kernel or ncat version related, but with libslirp 4.3.1 the --disable-dns did not show the expected timeout.

@AkihiroSuda in #234 (comment) :

timeout of what?

@mbargull in #234 (comment) :

https://github.com/rootless-containers/slirp4netns/blob/v1.1.6/tests/test-slirp4netns-disable-dns.sh#L33-L35 does not get a timeout message to grep for (the ncat seems to succeed).

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@AkihiroSuda, I don't know if you'd want to investigate this further. I'm just opening this here for demonstrative purposes.
Feel free to amend or close!

[AkihiroSuda]

Thanks, this seems to require investigation

[AkihiroSuda]

The test may work after rebasing with master, which contains a7d99af

[mbargull]

The test may work after rebasing with master, which contains a7d99af

IIRC, I tested it locally with that commit too and the ncat simply succeeded without outputting any timeout -- but it makes sense to rebase in any case!

[AkihiroSuda]

Vagrant itself uses 10.0.2.0/24, so it conflicts with slirp4netns 😭

[AkihiroSuda]

Being fixed in #240

[mbargull]

Oh dear, I doubt I would've noticed that as quickly as you did :D.
Thanks, superseded by gh-240.