We've just swapped isp and have set our network up exactly as it was. We are having really bad connection issues on our network to outside sites. Running Ping Tester we are getting about 13% loss when pinging google for ten minutes.

The weird thing is that when just one person is in the office it seems fine. It's only when others start using it that it starts dropping out all over the place. I know really nothing about network setup and realise that I'm out of my depth. Can anyone shed any light on why this might be happening (I bet it could be a million things) and how to solve it.

We are using a hardware fire wall (ServGate EdgeForce).


  • 1. What are you connected with locally, wifi? 2. Do you have any bandwidth limiting rules in the firewall? 3. Who configured your router for the new ISP? – NickW May 9 '13 at 9:28
  • Hi Nick, it's not wifi we are all (6 computers) set up on a network that worked fine before (and still works locally). My boss configured the new router. He kinda knows what he is doing.... – Adam May 9 '13 at 9:39
  • As far as I know there are no limiting rules in the firewall. – Adam May 9 '13 at 9:39
  • What kind of connectivity is it? From you to the ISP? – NickW May 9 '13 at 9:41
  • It's virgin media cable connection. – Adam May 9 '13 at 9:47

You are probably suffering from double NAT.

I just Googled double NAT and Virgin media ISP, and it looks like you are not the only one suffering from this problem.

If at all possible, avoid ISPs that perform NAT internally. The "public" IP address that your router gets when connected to the Internet should in fact be "public".

  • NAT does not incur latency, but it can make forwarding complicated. This sounds like a link stability issue. – SpacemanSpiff May 11 '13 at 3:09
  • The original question does not imply anything about latency, and neither did I. The question mentions 13% ping drops after changing ISP, and increased network connectivity issues when more than one person is using the Internet at the same time. "More than one person" made me think about NAT issues, which then led me to think that maybe the new ISP is using double NAT while the older ISP did not. – wookie919 May 11 '13 at 4:30

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