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Random and bizarre connectivity issues

Random and bizarre connectivity issues

Random and bizarre connectivity issues

I've been banging my head about this for awhile. I work for a school corporation with multiple locations. Every school is working fine except for one.

The basic setup is this:
All switches are new Procurve 2910s which connect to a Procurve 3500 (IP address From there it goes through an AT&T circuit back to the high school where it connects through another Procurve 3500 (IP: The default gateway on the workstations is

The problem we are having is random workstations cannot get out to the internet. They can ping 6.250 but not 6.251. They can also ping around the local network at the school. Just not outside of the school. A computer will not be able to connect for awhile then all of a sudden it can get back on the internet and browse with no issues. It happens in labs where one computer works fine but the other one does not. I can swap cables and ports but the computer that can't connect still can't connect and vice versa. But it's too wide spread of a problem for it to be something with the workstations because it happens every where in the building and to some network printers. Sometimes it will start working after a few minutes. Other times it takes a reboot. Sometimes it's down for hours. I can run a ping -t and get a constant request timed out for awhile before it starts getting replies. Then it has no problems pinging it and internet speeds are great.

So far we've swapped out the core switch (, rebooted everything repeatedly on both sides of the network (school and high school), checked everything on the server, compared switch configurations with other schools that are working, reconfigured the way switches are connected. Nothing has worked.

Any ideas? I've been working with a network engineer and we are both at a complete loss. I also posted this on the HP forum.

RE: Random and bizarre connectivity issues

This sounds like an IP address conflict. Are the workstations Static addressed or DHCP? Probably what is happening is when the mac address table entry on a switch times out the problem clears until the conflict resurfaces.

Marv ccna

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