Incomplete ARP's on a Class C Subnet

From this morning we've had around 6 users complain that they are not getting a network connection. On further investigation the device is getting an IP address and can be pinged locally but is unable to get off the site.

On checking the ARP cache on the 3750 the devices not getting off the network all have Incomplete next to there addresses, I've flushed the cache a number of times and it still comes back incomplete.

The devices plug into a 2950 which is connected to a 3750 that does all the routing off the LAN and its from the 3750 that we cannot see the devices in question.

Any help would be much appreciated.

Who is Participating?
I wear a lot of hats...

"The solutions and answers provided on Experts Exchange have been extremely helpful to me over the last few years. I wear a lot of hats - Developer, Database Administrator, Help Desk, etc., so I know a lot of things but not a lot about one thing. Experts Exchange gives me answers from people who do know a lot about one thing, in a easy to use platform." -Todd S.

if you can ping the local address that mean the interface it's good, but i suggest you ping the ethernet router, I maean the default gateway, if that work fine then the problem it's on the routing protocol..
try if you ping another computer from the same site the the problem in on the router..
but if you still wan to check the swicth , you can do that thru a console port or thru vlan. but to make it thru vlan you have yo had set the vlan1 password (that´s for administrative propose), and then check the port. to make sure it's no closed or blocked.
hope it can help
Can you ping the devices from the 3750?
Is the DHCP server also connected to the 2950 switch with the clients?
Sounds like a problem with the link between the two switches. Cycle power on both and see if they come up better, or check the uplink ports for error counters.

Are they on the same "block" on the switch?  The 2950 is modular, and while extremely rare, the individual modules can fail (very very rare).  I agree that a power cycle might fix it right up.  If not, look for layer 2 issues like collisions, etc.  Also make sure that the devices, if they are computers (not other things like routers, switches, etc) are set to auto-detect link speed on both the switch and the device.  If they are, try hard setting the link duplex and speed on both the device and the switch and see if that helps.  This could be an auto-negotiation issue.  

Hope this helps.

Experts Exchange Solution brought to you by

Your issues matter to us.

Facing a tech roadblock? Get the help and guidance you need from experienced professionals who care. Ask your question anytime, anywhere, with no hassle.

Start your 7-day free trial
It's more than this solution.Get answers and train to solve all your tech problems - anytime, anywhere.Try it for free Edge Out The Competitionfor your dream job with proven skills and certifications.Get started today Stand Outas the employee with proven skills.Start learning today for free Move Your Career Forwardwith certification training in the latest technologies.Start your trial today
Network Operations

From novice to tech pro — start learning today.