ramblings…

Last morning the Internet connection through my Draytek 2910 at home failed. Usually restarting the Draytek would fix it. This time it refused to come back up. Then I connected a PC directly to the GPON device and created a PPPoE dialer on WinXP and the connection came up in a flash! That’s strange, I thought. Plugged the DrayTek back and tried changing the MTU, the PPP authentication and some other parameters. No luck.
Had a chat with Troy about this strange behaviour, he was also stumped.
The ISP tech came over this morning and meddled around with the device and no luck. I suggested that he connect the ISP standard router and configure it with my PPPoE parameters. He did and the link came up! So he left with the factually correct but useless  statement that “something was wrong with the Draytek”

Next I wiresharked the line to see what was going over the wires. I noticed the PADI was going out with the display name I’d configured on the Draytek for this connection! So obviously the so-called Display Name was NOT just that… it was being actively used as the service name in the PPPoE conversation.

Troy called me just then, after some discussion with his cronies and suggested that I remove the display name. The wireshark log confirmed Troy’s statement and figured that this must be the reason. Blanked out the Display Name in WAN Setup and… I had working Internet!

So now, its clear that something changed at the ISP end (although they vehemently denied it), since this device was working fine with these parameters till early last morning.

The Draytek 2820Vn is a great device for home and small-offices. It has two WAN ports; ADSL and Ethernet. Excellent VPN capabilities 32 simultaneous VPN tunnels (IPSec, PPTP, L2TP and L2TP over IPSec.)

In order to get point to point voice working either on VPN or LAN you need to ensure that

1. the “External IP :” under VoIP -> SIP Accounts is the private IP of the router itself
2. the SIP account in use is configured with  “Register via  LAN/VPN”
3. “NAT Traversal Support” is set to “None”

Troy was trying in vain to get voice calls working. We hit on this combination after quite a bit of messing the parameters. The predecessor of the Draytek 2820Vn (the Draytek 2800VG) does not need these fiddly parameters configured and works just fine without these settings. This coupled with the fact that he’s bought 5 of these devices to internetwork the branch offices of a relative’s company, caused this networking boffin a lot of frustration.

Troy has since gone back to meddling with his favourites Cisco and HP ProCurve, thankful to your truly for having helped put this ordeal behind him!