My company recently purchased a DrayTek Vigor 2920n to replace an ancient Linksys router that connects to the office DSL service (AT&T). As it's a DSL service from AT&T, the router WAN connection is configured for PPPoE with an MTU of 1492. I've disabled all features in the router except for DHCP and a few NAT port redirections to servers on the internal LAN. Everything on the LAN side runs great, but I'm getting 20%+ packet loss over the WAN interface when sending PINGs to remote addresses. The old Linksys BEFSR41 that we're attempting to replace has 0 packet loss over the WAN.

The DSL modem we have from AT&T is a SpeedStream 5360 (060-5360-002), if that matters.

I'm no networking expert, but I think the configuration is pretty sound here. Is there something obvious that I'm missing that could be the source of the packet loss over the WAN interface? Does anyone know what to look for to attempt to diagnose the issue?

Thanks in advance.

  • How are you measuring the packet loss? Simple PING to an address or? – Dave M Mar 17 '11 at 17:53
  • Just a simple ping. I've tried pinging several sites with both routers. All pings going through the DrayTek show 20%+ packet loss. All pings on the Linksys go through just fine. – Grant Limberg Mar 17 '11 at 17:56

how do you connect your router to the lan? can it be that it's autonegotiation missmatch - eg router thiniking it's fast ethernet full duplex while the switch - half duplex?

  • Router is connected to a Netgear 16 port gigabit switch. All LAN ports on the router are gigabit as well. There is no packet loss between the LAN and the router itself. I can ping -f the router all day with no packet loss from within the LAN. Only having problems on the WAN side. – Grant Limberg Mar 17 '11 at 20:47

From the looks of the DrayTek Support site, they just release a new firmware revision ( for your model which seems to correct a large number of problems. I'd be surprised if anything needed to be adjusted out of the box in order to make it work, but your best bet is to make use of your support contract with DrayTek and your ISP.

  • I've installed the latest firmware ( hoping that will fix it. I've yet to test it, though. I have to wait until most of the employees leave for the day so I'm not interrupting everyone – Grant Limberg Mar 17 '11 at 20:20

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