1 of 2 computers can't ping router.

[Peli147]

Hi all, not sure if this is in the right place as I'm fairly sure it's not a router issue, if so please show me where the correct place is.

I'm having a problem where I can't connect to the internet on my computer. Everything is working fine on a second computer connected to the same router, and everything was working on the first computer until a couple of days ago when I did a hard reset.

Details:
Router: Billion Bipac 7800NL (ethernet connection)
OS: Windows 7 64bit
Motherboard: Asus Z87-Plus

Things I've tried so far:

• 
  Turning off/on the computer and router.
  Using the ethernet cable and router port from the working computer.
  System restore.
  Turning off the firewall.
  Reinstalling the LAN drivers.
  Restoring the router to factory defaults.
  netsh int ip reset & netsh winsock reset
  Setting a static IP address.

Still nothing. Cannot login to the router from that computer or even ping the router (100% packet loss). Everything still working as normal from the 2nd computer as well as for a handful of wireless devices.

When set to DHCP (which works normally) I obtain an IP address such as 192.254.x.x, which I'm fairly sure is bad. There are definitely enough IP address available on the router.
When I set to static IP address I obtain the IP address I set, but still can't ping the server or connect to the internet.

I should add that the LED on the router is green and shows a connection, and the LAN port LEDS on the motherboard show a connection, although the speed is indicated as less than the normal 1000Mbps.

I'm fairly sure it's something driver related in windows 7 or the ethernet port on my motherboard has died. The only thing left to do I can think of is reinstalling windows or try to RMA the motherboard, but I'm trying to avoid these.

Any suggestions? Let me know if you need any more info. Can post IPconfigs if required.

Thanks.

 

[FiL]

obvious stuff first.

make sure you assign a static IP address that is in the same subnet as the router's management IP.

bring up TWO terminal windows

firstly leave a continuous ping running in one

"ping -t <IP ADDRESS OF ROUTER>"

in the second check your layer 2 cache

"arp -a"

do you see what looks like a valid MAC address for the router? or is this aging out

 

[Peli147]

obvious stuff first.

make sure you assign a static IP address that is in the same subnet as the router's management IP.

The routers DHCP server can assign Ip adresses of 192.168.1.1-20. I have assigned a static IP of 192.168.1.16, which wasn't assigned to anything. Is this what you mean? For subnet I used the same one that shows on the working computer.

bring up TWO terminal windows

firstly leave a continuous ping running in one

"ping -t <IP ADDRESS OF ROUTER>"

in the second check your layer 2 cache

"arp -a"

do you see what looks like a valid MAC address for the router? or is this aging out

I've done this on both the working and not working computers.

On the working computer (using DHCP) the first window continuously reads "Reply from 192.168.1.254(my routers IP): bytes=32 time<1ms TTL=64"
The second window shows a correct mac address for the routers IP, the same mac address I can see in the routers info page.

On the not working computer, the first window coninuosly reads "reply from 192.168.1.16(the IP I assigned, which is strange): Destination host unreachable" with the occasional "Request timed out"
On the second window the IP address for my router is not even listed.


Quick question, when setting the static IP, should my DNS servers be the two listed on my routers info page (61.9.x.x) or the one listed when I ipconfig from the working computer (192.168.1.254, the same as my router/default gateway/DHCP server)? I'm currently using the first option.

 

[FiL]

for DNS it shouldn't actually matter. you could even use google's public DNS.

but whilst you can't reach your default router this is all moot.

make sure your subnet mask is the same on all the boxes, as you are all on the same subnet, you'll need the same mask as whatever is on the router.

one question, can you ping across the LAN? (computer to computer)

 

[Peli147]

So I came home try what you said and everything was working fine. I'm very confused, but glad it's working. Thanks for your replies.

 

[FiL]

good to hear it's fine, it's baffling that one PC couldn't reach anything for a while, it might have been a short lived corruption in loading the network card drivers i guess...or an over zealous software firewall.