Help needed: cannot send packets larger 230 bytes via vodafone umts

[Andrew Gordon]

On Tue, 11 Oct 2005, Rehsack Jens (ext) wrote:
> > >
> > > So I figured out how to configure ppp (it's not trivial! ;-)) and
> > > after around 5 or 6 hours I get it run that way, that nslookup
> > > & ping works ...

Your ppp.conf looks a bit more complex than needed, but on the other hand
doesn't seem to contain the "AT_opsys=3,2" to request UMTS (versus GPRS).
Maybe your card defaults to UMTS.

Mine looks like:

2g:
 set device /dev/ucom0
 set ifaddr 10.0.0.1/0 10.0.0.2/0 255.255.255.0 0.0.0.0
 add default HISADDR
 set phone "*99***1#"
 disable lqr
 set timeout 0          # Disable timeout
 set dial "ABORT BUSY ABORT NO\\sCARRIER TIMEOUT 5 \
           \"\" AT OK-AT-OK AT_opsys=0,0 OK \\dATDT\\T TIMEOUT 60 CONNECT"

3g:
 set device /dev/ucom0
 set ifaddr 10.0.0.1/0 10.0.0.2/0 255.255.255.0 0.0.0.0
 add default HISADDR
 set phone "*99***1#"
 disable lqr
 set timeout 0          # Disable timeout
 set dial "ABORT BUSY ABORT NO\\sCARRIER TIMEOUT 5 \
           \"\" AT OK-AT-OK AT_opsys=3,2 OK \\dATDT\\T TIMEOUT 60 CONNECT"



Note that this is for the Vodafone-branded 'Option' cardbus card, which
contains a USB controller and a USB serial port (as discussed on this
mailing list a week or so ago).  I use the '2g' entry in ppp.conf to avoid
roaming onto 3G networks which have voice interworking with Vodafone but
not data (this may not be as much a problem now as it was last year, but
in any case with roaming charges so high, slowing down to GPRS rates when
roaming is no bad thing).


> And horribly I had to see, that traceroute seems to transport even
> larger packets an get's the wanted answers. I also tried after that
> shock >traceroute -P TCP< and seen, that it works, too.
>
> But an >echo "GET /
> " | telnet www.uni-halle.de 80< didn't get any answer (keeps empty).

I'm fairly sure that Vodafone have a transparent proxy on port 80.  It
used to be a specialised one that replaced graphics files in web pages
with more-heavily-compressed versions of the original file, though that
might be only when using GPRS rather than 3G.

Did you try something like ssh?

Note also that Vodafone are certainly doing NAT.


[All the above based on Vodafone UK behaviour, and roaming to various
places; I've not actually tried it in Germany].