[Tcsh] [PATCH] REMOTEHOST causes hang with IPv6 addresses

[Kimmo Suominen]

On Sat, 25 Feb 2023 at 01:22, Chuck Anderson <cra at fea.st> wrote:
> If you open the bugzilla link, you can find the versions and system
> being used.  In summary:
>
> tcsh-6.24.07-2.fc37.x86_64 (Fedora 37)

Thanks. I did open the link, but this information did not stand out to
me. Not that I was sure whether you were running the same setup as in
the bugzilla ticket to begin with...

> I don't want the shell doing any built-in DNS resolution at all,

It would be nice if this were configurable. Patches and pull requests
are welcome.

> unless I configure or script that feature.  There is too much
> variation and complexity in different DNS resolver
> configurations/nsswitch/etc, and one would have a tough time
> convincing the systemd maintainers to change how it does "local"
> resolution (names without dots)--I've see the discussion threads.

However, if you are using systemd-resolved and are not using LLMNR or
mDNS on your network, it is probably well worth while editing
/etc/systemd/resolved.conf to disable them:

[Resolve]
LLMNR=no
MulticastDNS=no

> However, it would be nice if it parsed utmp correctly to set
> REMOTEHOST to IPv4 and IPv6 addresses.  Right now I get no REMOTEHOST
> at all if it is an IPv6 address (after it times out trying to resolve
> fdd1).

I will work on fixing this. The current logic is from well before
IPv6, and needs updating.

Cheers,
+ Kimmo