Dears,
I'm trying to setup LEDE to use a VOIP soft-phone connected to my LAN.
SIP is handled correctly thru UDP port 5060, forwarded to soft-phone IP.
RTP (audio) doesn't work unfortunately as I understand I would need a STUN client to get that thru (my VOIP provider running a STUN server).
Would anyone has a clue on how to set that STUN client up on a LEDE router?
I came upon that article yes and assumed it'd be an easy one...
Unfortunately I did not find any stun-client package for LEDE 17.x but only an archive for OpenWrt 14.x
https://archive.openwrt.org/barrier_breaker/14.07/ar71xx/generic/packages/oldpackages/
Can a 14.x package work?
Is there any updated version of this package?
I am on OpenWrt 18.06.2 but I also do not find the stun-client package.
BTW, I am trying to set up SIP/VoIP access to Deutsche Telekom with no luck so far...
Any hint welcome.
In most cases STUN is not required. If your SIP provider cannot properly serve NATed clients - just get rid of such provider.
Maybe siproxd would work for you. It's not a STUN client, it sits on the router and rewrites SIP messages. My guess is that it can also take care of RTP.
siproxd is not required as well as any other SIP ALG implementation.
Don't rewrite anything - be honest with your provider 
That is completely unrelated to OpenWrt.
Well, you can't just blame it on the provider. NAT and SIP aren't the best friends. When the provider receives a message that you're gonna use IP/port X but then you're using IP/port Y due to NAT, that's not nice 
That is not an issue at all, there is a common technique to handle such situations on a VSP side. Again, there is no single problem with OpenWrt here.
Doesn't your phone have STUN client included so you can just configure the DTAG STUN server?
The question is where is the stun-client package referred to in the documentation?
STUN client is an attribute of a SIP endpoint, not a router.
You can use any public STUN server on Internet and there're other options available to perform the same task (to trick VSP), like using rport.
It looks like that package was part of the old openwrt-packages feed and never got ported to the new packages feed. And upstream seems dead anyway, see here.