Can ping any IP address but gettings timeouts on one IP

hamesy · 8 Feb 2010 at 15:21

Little bit of a weird one.

We've got a Windows 2000 Server at work which can ping any IP address on the network, including any public IP address. However, when we ping a router we get the timeouts. At first we thought the router was playing up, but when we ping the router from different machines, we get no timeouts what so ever.

Any idea's what might be causing this?

rz30 · 8 Feb 2010 at 17:53

Is it SBS 2000?

"a router" or "the router" ?

J.B · 9 Feb 2010 at 08:17

Thats very odd, could you go in to a bit more detail about your setup, what kind of router are you using, any additional switches involved? etc...

hamesy · 9 Feb 2010 at 09:06

Basically from the server it does:
Win200 Server->3com switch->Cisco switch->fibre->Cisco switch->Draytek router

We've replaced the 3com switch has we've had issues with that before with timeouts.

But the weird thing is, we've got other server's attached to that 3com switch without any problems.

The Draytek in question is used for a VPN connection to another site.

PistolPete · 9 Feb 2010 at 11:08

Has this worked before? Is the IP setup 100% correct (mask and gateway?)

hamesy · 9 Feb 2010 at 11:30

Working perfectly fine upto until last week. Nothings changed apart from replacing the 3com switch, but even before we replaced the 3com switch the issue was still there.

SMN · 9 Feb 2010 at 12:34

"arp -a" to make sure its got the right MAC to IP entry? Bit odd, but why does this matter? Router may have some quirky ICMP rules to stop it getting PoD'd from the WAN and may be getting confused beetween the 2. Maybe bounce it also.

hamesy · 9 Feb 2010 at 12:48

MAC to IP entry is correct.

We've had a look at the router and couldn't see anything. But if the router had from ICMP rules, then surely we would get timeouts from the other machine on the network when we ping the router?

DiscoDave · 9 Feb 2010 at 12:55

Tried changing the buffer size to something very small? ie ping [ipaddress] -l 16. Shot in the dark I know but just incase..

Anything odd in the event viewer?

PistolPete · 9 Feb 2010 at 17:20

Can you check the ARP of the hosts on the router itself at all??
Maybe it's trying to send the replies to another MAC?

hamesy · 10 Feb 2010 at 10:23

Thats interesting. When I checked the arp entry on the router for the server, everything was fine. Checked it again this morning and its showing a different mac address. Been monitoring it for the last 30 minutes and its constantly changing.

Only problem is I can't find the mac address on the network.