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DanJournoFlag for United Kingdom of Great Britain and Northern Ireland

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Network Issues

Hi,

A client is having intermittent network issues.
They've replaced their Switch and their ADSL router.

However, they are seeing intermittent problems with DNS resolution.
NSLOOKUP shows that the problems occur even when using opendns.org and Googles DNS servers.

Could a machine on the network be causing this issue?
I've worked through each machine and disconnected one by one to try to locate it but can't seem to locate an issue.

They are also seeing the occasional high ping of 190ms when pinging any machine on the network. I've never seen that when pinging a local machine.

Reply from 192.168.12.1: bytes=32 time<1ms TTL=64
Reply from 192.168.12.1: bytes=32 time<1ms TTL=64
Reply from 192.168.12.1: bytes=32 time<1ms TTL=64
Reply from 192.168.12.1: bytes=32 time<1ms TTL=64
Reply from 192.168.12.1: bytes=32 time=1ms TTL=64
Reply from 192.168.12.1: bytes=32 time<1ms TTL=64
Reply from 192.168.12.1: bytes=32 time=190ms TTL=64
Reply from 192.168.12.1: bytes=32 time=190ms TTL=64
Reply from 192.168.12.1: bytes=32 time<1ms TTL=64
Reply from 192.168.12.1: bytes=32 time=190ms TTL=64
Reply from 192.168.12.1: bytes=32 time<1ms TTL=64
Reply from 192.168.12.1: bytes=32 time=190ms TTL=64
Reply from 192.168.12.1: bytes=32 time<1ms TTL=64
Reply from 192.168.12.1: bytes=32 time<1ms TTL=64
Reply from 192.168.12.1: bytes=32 time<1ms TTL=64
Reply from 192.168.12.1: bytes=32 time=190ms TTL=64
Reply from 192.168.12.1: bytes=32 time<1ms TTL=64
Reply from 192.168.12.1: bytes=32 time<1ms TTL=64
Reply from 192.168.12.1: bytes=32 time=190ms TTL=64
Reply from 192.168.12.1: bytes=32 time<1ms TTL=64
Reply from 192.168.12.1: bytes=32 time<1ms TTL=64

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It's quite urgent as the client's getting really annoyed.
Avatar of giltjr
giltjr
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What is the DNS resolution problem?  No name returned, or the wrong name?

Is the switch managed?

What is 192.168.12.1?  The switch or the ADSL modem?
Also, is this happening across all the client machines or just some?
Avatar of DanJourno

ASKER

Seems to be a faulty network card in the new server affecting all other network traffic.

Just in case a replacement NIC doesnt resolve it, here are the answers to your questions....

What is the DNS resolution problem?  No name returned, or the wrong name?

 - No response. Just a timeout.

Is the switch managed?

- No. :-(

What is 192.168.12.1?  The switch or the ADSL modem?

- Its the ADSL router.

Also, is this happening across all the client machines or just some?

- All PCs lose network access when the issue occurs. Ping doesnt work. No data at all to any IP address.
Avatar of andyb1rd
andyb1rd

the problem to me sounds like the unmanaged switch doesnt have enought of a buffer, and is full.

does the network work ok for a while when its reset?

if this is the case then the switched would need to be changed.

the reason why its happpening is because the switch is having to buffer traffic going to the dsl which has a lower through put to the internet, this then causes the switch to loose packets when its full which then causes your pings to go up.

the best answer to resolve this is to get a managed switch like cisco which then can buffer traffic much better and also debug network traffic much better.
ASKER CERTIFIED SOLUTION
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DanJourno
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The problem hasnt occured since we replaced the network card in the server.
It appears that the faulty card was interrupting all traffic on the network.