[Galene] log message: failed to resolve stun host

[Galene] log message: failed to resolve stun host

[Michael Ströder]

HI!

While everything seems to work I'm not sure if things are optimal.

In the logs I saw a message like this (example hostname):

failed to resolve stun host: turn.example.com:443: address
turn.example.com: no suitable address found

At this time turn.example.com was a CNAME for A RR turn1.example.com
pointing to the real IP. The PTR RR for the IP address pointed to
turn1.example.com.

Does ICE require hostname used in turn-URL and PTR RR for the resolved
IP address to match?

Ciao, Michael.

[Galene] Re: log message: failed to resolve stun host

[Juliusz Chroboczek]

> failed to resolve stun host: turn.example.com:443: address
> turn.example.com: no suitable address found

Interesting.  Could you please recompile with

  CGO_ENABLED=1 go build -ldflags='-s -w'

and see if the issue goes away?

Explanation: the go stdlib has two DNS resolvers, one written in Go and
one that calls the one libc.  If you compile with CGO_ENABLED=0 (which is
the default when cross-compiling), you get a static binary, and the Go
resolver is used unconditionally.  If you compile with CGO_ENABLED=1, then
the binary is linked against libc, and the native resolver is called.

-- Juliusz

[Galene] Re: log message: failed to resolve stun host

[Michael Ströder]

On 1/8/21 7:36 PM, Juliusz Chroboczek wrote:
>> failed to resolve stun host: turn.example.com:443: address
>> turn.example.com: no suitable address found
> 
> Interesting.  Could you please recompile with
> 
>   CGO_ENABLED=1 go build -ldflags='-s -w'
> > and see if the issue goes away?

I wouldn't call it an issue yet. Maybe it's just an overzealous log
message of a gracefully error handling.

> If you compile with CGO_ENABLED=1, then
> the binary is linked against libc, and the native resolver is called.

Ok.

# ldd /usr/sbin/galene
	linux-vdso.so.1 (0x00007fff75fc1000)
	libpthread.so.0 => /lib64/libpthread.so.0 (0x00007f2088482000)
	libc.so.6 => /lib64/libc.so.6 (0x00007f20882b7000)
	/lib64/ld-linux-x86-64.so.2 (0x00007f20884ac000)

Makes no difference. Also the hostname in the turn-URL now is an A RR
with matching PTR RR.

Ciao, Michael.