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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).

Thanks!

Adam
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  • 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 09 '13 at 09:28
  • 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 09 '13 at 09:39
  • As far as I know there are no limiting rules in the firewall. – Adam May 09 '13 at 09:39
  • What kind of connectivity is it? From you to the ISP? – NickW May 09 '13 at 09:41
  • It's virgin media cable connection. – Adam May 09 '13 at 09:47
  • Oh lord :) This is probably going to be an issue with the modem they gave you, possibly it has limitations on the amount of concurrent NAT sessions, or something memory based. Is the package a "business" class one, did they provide the modem/router? – NickW May 09 '13 at 09:50
  • They didn't give us a modem. We are using the same kit we had before which worked perfectly with a 100mb line. I'll look into the NAT sessions but its the same gear we were using before and all worked fine for everyone. – Adam May 09 '13 at 09:57
  • As I said, I don't really know loads about all this and will probably not be able to give you all the info you need to help very well so feel free to stop at any point! – Adam May 09 '13 at 09:58
  • I'm referring to the bit that converts the cable (the coaxial wire) to ethernet (what connect to your computer, eventually). Anyhow, I'd get into contact with virgin, it could be something wrong with the line, they can do remote diagnostics to rule that out, but you do need to find out if they have given you business style equipment, the consumer style things are not meant for serious usage by more than a few people. I don't think the problem is with your infrastructure, but with the virgin equipment (or their line). – NickW May 09 '13 at 10:02

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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".

wookie919
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  • NAT does not incur latency, but it can make forwarding complicated. This sounds like a link stability issue. – SpacemanSpiff May 11 '13 at 03:09
  • 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 04:30