We have a few branch offices with adsl connections (ISP's are Demon or Onyx). Each branch office has a draytek 2820 and a sonicwall (model: tz170 or tz180) which provides a site-2-site vpn connection back to head office... yes i know we could do this without the Sonicwall but we make use of their other features too.

Any how... we just opened a new branch office and they went for a BT 20mb ADSL2+ connection. The adsl connection comes with a block of 5 static ips. So yesterday I setup the draytek and sonicwall in the usual manor, configuring the Dratrek with the first static ip and the Sonicwall with the second. This works fine, the sonicwall provides dhcp for the branch office workstations and they can access the internet and head office servers via the site-2-site vpn. However, the sonicwall loses its connection to the internet every few minutes. After a few minutes the connection comes back and then drops again. This process repeats constantly.

To trouble shoot i did the following:

- updated the draytek firmware
- updated the sonicwall firmware
- added the block of 5 static ips to the wan aliases and nat pool on the draytek
- replaced adsl filter
- swapped out both the draytek and sonicwall

Has anyone else had similar issues? Any suggestions or advise would be welcome ;)