We help IT Professionals succeed at work.

Network problem effecting three servers

Medium Priority
213 Views
Last Modified: 2012-05-12
We have three servers with fixed IP's up until yesterday morning all was working OK and has been for some time.   Then I had reports of no email coming through on closer investigation the W8K server reports that it is connect to the local network but has no internet access.  The same on two other servers all internet facing.

For other PC's and servers on the netwoek we have no problems just these three servers, I have checked cables, Network settings rebooted the router, firewall and switches but still the same.

If I remove the fixed IP and let DHCP allocate an address it will connect to the internet which I dont get why?

Please help!

Thanks

Andy
Comment
Watch Question

Kruno DžoićSystem Engineer

Commented:
try this:

cmd

command: ping www.google.com and tracert www.google.com

what is the result?
Sikhumbuzo NtsadaIT Administration

Commented:
Have you tried changing the IP addresses and test?
Are the servers logged in with the same username, is it not locked?
Can you do a (nslookup to www.goolge.com) then post results?

Author

Commented:
Pinging google gives the following

pinging google 209.85.169.106
request time out X4

tracert
all time out

nslookup

server: qcl-comms2
address:  192.168.0.4

non authorative answer
209.85.169.105
209.85.169.147
209.85.169.99
209.85.169.104

If I remove the fixed IP and let DHCP allocate address ping to google works.  tracert works nslookup gives the same response as before
Sikhumbuzo NtsadaIT Administration

Commented:
Then there is IP conflicts - verify that there is no other SERVER/COMPUTER is using the same IP addresses.

 
Sikhumbuzo NtsadaIT Administration

Commented:
Also double check that the DNS server that is issued by DHCP is the same as the one you enter on the statis IP addresses.

Author

Commented:
How would I do this?  and why would this just suddenly happen when the fixed IP's are not in the allocated range
Sikhumbuzo NtsadaIT Administration

Commented:
You can use a program call angryIPscanner download it.

Put your server on DHCP, then run that program to check which IP addresses are available - it will indicate which PC is using your server's IP address. Then you can go to that PC and remove it. On your Scope try and exclude a range that will not be assigned by DHCP..


Example: 172.16.0.1 - 172.16.0.200 is used by my servers and routers, printers, switches on our network.

It is excluded on the DHCP scope.

 

Author

Commented:
I left the fixed DNS address's as they are when changing to dhcp
Sikhumbuzo NtsadaIT Administration

Commented:
Chances are your IPs are marked as bad IP addresses in DHCP - open up your DHCP console and see if they are not marked.

Then go back to your server do a "ipconfig /flushdns" and "ipconfig /registerdns" and try again.



Author

Commented:
having trouble checking the dhcp server for marked address's.  This is a W2k3 box how would I do this?  Or shall I just reboot it?
Top Expert 2011

Commented:
Check system logs on your servers, most often there are logs showing IP conflict and MAC address of the device, with which this conflict occurs
Sikhumbuzo NtsadaIT Administration

Commented:
Hi just got back, what is the latest on this? What have you tried so far? Are you still having problems with the internet, can you change the IP addresses temporarily and leave it over night if possible then, we can troubleshoot why the IPs get assigned?



It turns out the company who manage our firewall for us ran an update on it yesterday and something didn't quite go right!

Author

Commented:
Because thats what happened

Explore More ContentExplore courses, solutions, and other research materials related to this topic.