Hi all

I have a Vigor 2820n which is connected directly to an ADSL line.

2 or 3 times a day on average, all devices connected to the router suddenly lose internet access. The online status page shows that it is still connected as normal however.

All devices can ping the router no problem but any ping to a web address fails.

It will not return until you either reboot the router, either through the browser or by physically powering it off and back on.

The ISP have tested the line and found no problems.

All devices on the LAN remain connected and have no problems accessing each other.

Whilst the internet is unavailable to the LAN, the router can still be pinged externally to the WAN port's external IP address. Therefore it is still connected to the internet, it just doesn't seem to be bridging the WAN and LAN together.

After rebooting, it will work as normal for either a few minutes or few hours and will then happen again.

Any help would be very much appreciated. Thanks in advance.

it sounds like your DNS resolution is failing.

When you get a failure, from a ( Windows ) command line, do a nslookup of google.co.uk, or bbc.co.uk

also, bring up a browser and goto http://216.58.209.227/

That is google.co.uk - if the page appears when you use an IP address but not when you use a name, then either
1. the DNS server you use is breaking, or
2. the router is not handing out the DNS server address to your network clients.

hope this helps

Martin

also try lan>general setup>details page & set the dns of your isp or any one
On exit again at lan > general setup if your model has the option Force router to use "DNS server IP address" settings specified in .. tick it

Thank you for your replies.

Whilst the issue is occuring, nslookup always fails. DNS request to my.router timed out each time.

Trying to ping or visit an IP also results in no connection, so I'm thinking it's probably not a DNS issue. The same thing occurs when using a custom DNS.

What I have just noticed is that after 10 minutes or so it will return to normal without having to reboot any connections resetting.

I took the following from the data flow monitor immediately after it dropped out. Not sure if this shows up anything:

Index TX rate(Kbps) RX rate(Kbps) Sessions
Current / Peak / Speed Current / Peak / Speed Current / Peak
WAN1 6 / 301 / Auto 12 / 7170 / Auto ---
WAN2 0 / 0 / Auto 0 / 0 / Auto ---
Total 6 / 301 / Auto 12 / 7170 / Auto 93 / 617

I'm still baffled.

I've noticed that pinging an IP always works when the issue is occuring. No problems there.

I can even ping the DNS IP yet an nslookup will fail.

I've even tried using Google's public DNS 8.8.8.8 both on the router and set manually on each PC. Even when set on the PC an nslookup will fail even though I can ping it.

It's like the router is letting nothing through except ping packets :?

Not sure if is bug from the unit ... but have tried latest firmware 3.3.7.6 (with *rst* file (rst will set everyhting back to factory defaults)? if will help & if you do update consider the released notes for having minimum issues?
http://www.draytek.com/index.php?option=com_jumi&view=application&fileid=15&Itemid=583&lang=en

IMPORTANT NOTE: Do not upgrade directly from 3.3.5 (and earlier) to 3.3.7.5.
Due to differences in the Web UI and functionality the router MUST first be
upgraded to 3.3.5.2 prior to upgrading to 3.3.7.5.

Upgrade your router to Version 3.3.5.2 first, and afterward upgrade the router
to Version 3.3.7.6

.