Path: csiph.com!weretis.net!feeder8.news.weretis.net!reader5.news.weretis.net!news.solani.org!.POSTED!not-for-mail From: Richmond Newsgroups: uk.telecom.voip Subject: Re: About 5% of outgoing calls fail with one-way sound only - fix? Date: Sat, 24 Jan 2026 10:44:12 +0000 Organization: Frantic Message-ID: <82ms23i937.fsf@example.com> References: <82v7gsiay4.fsf@example.com> <82cy30gd9r.fsf@example.com> MIME-Version: 1.0 Content-Type: text/plain Injection-Info: solani.org; logging-data="688759"; mail-complaints-to="abuse@news.solani.org" User-Agent: Gnus/5.13 (Gnus v5.13) Cancel-Lock: sha1:JcjfOsWJbNPL5FmN6VAZUhlFbDo= sha1:AvIDAHNvWeMKiILOi/lD1uPvW2k= X-User-ID: eJwFwQEBwDAIAzBLlNECds6HfwlLeARNhqjgcnPHDthd9Jx2eaK9ugG6XaZQX+CvMLu1eOtkDzc= Xref: csiph.com uk.telecom.voip:9101 Chris Green writes: > Richmond wrote: >> Chris Green writes: >> >> > Richmond wrote: >> >> Chris Green writes: >> >> >> >> > Our VOIP is a straightforward (?) Yealink DECT system, a W70B >> >> > base station and five W73H handsets. It works well for most >> >> > calls but a small percentage of outgoing calls fail with 'them' >> >> > being able to hear 'us' but we can't hear them. >> >> > >> >> > These are always (so far) calls to businesses or local >> >> > government, however it is just one or two that fail, most calls >> >> > to banks etc. work perfectly OK. It's consistent with any >> >> > particular destination, if it doesn't work first time then it's >> >> > never going to work. >> >> > >> >> > We're with Plexatalk whose 'support' (it's a one man band I >> >> > think) has disappeared for the moment. >> >> > >> >> > Is there an 'obvious' fix for this? Is it something awry at >> >> > Plaxatalk? Is it worth trying another VOIP provider (I'm >> >> > tempted, given the lack of response at Plexatalk)? >> >> >> >> I had a similar problem and I fixed it by switching on SIP ALG, >> >> which is frowned upon. But it could be the same underlying problem >> >> of packets not being routed back to the right address, because >> >> there is no stun server perhaps. >> > >> > It's enabled, maybe I should disable it as recommended by most. It >> > was enabled by default, I didn't do it. >> >> You could try disabling it as can cause problems depending on the >> implementation. >> >> I am using ipv6 but that didn't help me at all because I am still >> behind NAT. >> > Surely, in the main, if you have IPV6 there's no NAT involved is > there? That is the case with my mobile devices I think, as they have unique public IP addresses and I never had any problem using the Linphone app. But the other phones I have are analog DECT phones, and they are plugged into the router, so they don't have their own IP address or MAC address, they share the router's. As I understand it, with SIP, the outgoing packets can contain local IP addresses anyway, so if it is a local ipv6 address beginning with fe80:: that wouldn't be any use either. I never got to the bottom of what was happening with my system because I could not look at the packets. These local addresses are in the payload of the packets. Your Yealink devices might be quite different.