Date: Wed, 18 Jan 2012 07:35:49 +0100 From: Matthias Apitz <guru@unixarea.de> To: Maciej Milewski <milu@dat.pl> Cc: freebsd-net@freebsd.org Subject: Re: PPP to UMTS provider && incoming traffic (TCP, UDP) Message-ID: <20120118063549.GA2742@tinyCurrent> In-Reply-To: <1784936.VLDeoQkidl@snifi> References: <20120117190847.GA1255@tiny> <1784936.VLDeoQkidl@snifi>
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El día Tuesday, January 17, 2012 a las 11:43:15PM +0100, Maciej Milewski escribió: > Dnia wtorek, 17 stycznia 2012 20:08:48 Matthias Apitz pisze: > > Hello, > > > > I'm used to connect my FreeBSD 10-CURRENT netbook to Internet via PPP; > > the provider in question is a German O2 UMTS provider; so far so good, > > i.e. all is working as it should: outbound HTTP, SSH, SMTP (I'm just > > sending this mail through such a connection), ... > > > > what does not work is VoIP; the call is established via SIP (using a > > STUN server), but remote audio RTP packages are not coming down; I > > checked this with TCPDUMP: only upstream RTP is send, no incoming UDP; > I observed similar problem with L2TP VPN and for me it looks that they are > blocking incoming/returning UDP traffic in public APN. > On the server side I see both incoming and outgoing traffic but device > complains that it's unable to connect. If I switch to local wireless network > then everthing works fine. I suspect that's because they are selling > special(money) APNs. Thanks for your feedback; I think too, that UDP downstream is blocked if there is not upstream UDP initialized for the same socket pair; and VoIP is using different UDP ports for up- and downstream media (audio). What I'm wondering is, how does Skype works (which is fine with my UMTS provider at the same time), have to check this with TCPDUMP... matthias -- Matthias Apitz t +49-89-61308 351 - f +49-89-61308 399 - m +49-170-4527211 e <guru@unixarea.de> - w http://www.unixarea.de/ UNIX since V7 on PDP-11 | UNIX on mainframe since ESER 1055 (IBM /370) UNIX on x86 since SVR4.2 UnixWare 2.1.2 | FreeBSD since 2.2.5
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