[vpnc-devel] Problems with vpnc connection over GPRS

[mabo76 at seznam.cz]

Hello,

I was not able to establish VPN while connected to internet by mobile phone. I repeatedly got following error:

vpnc: expected xauth packet; rejected:  (ISAKMP_N_PAYLOAD_MALFORMED)(16)                 

Everything worked fine when I was connected through reasonable internet connection (cable).

The problem is in connection high latency and small speed. Packets are resend during connection negotiation and it leads to vpnc confusion ending with the error. 

The problem can be solved by increase of packets resend timeout. Everything started to work for me after I changed this source line

vpnc.c: line 3271 (vpnc version 0.5.3)
	s->ike.timeout = 5000;

Maybe it would be usefull to make this constant settable from command line.

If anybody wants to analyze why vpns gets confused, I can send debug output and packet's dump for both successful and unsuccessful connection negotiation.

Best regards

Martin Bouzek