Ive had 3 IT guys look at this issue.
Our internet drops every 5 minutes for 30 seconds then reconnects.
we have replaced all networking gear and routers.
We have applied all software and firmware updates.
we have replaced all networking devices.
We have got the landlines phone lines tested and they have come back OK.
we have tested with and change service providers.
This issue happens on 3 of our pc connected to the network.
2 x desktops
2 x laptops.
wireless connections. Tried network cable and same issue.
we have sbs 2003. all clients running xp.