Devices Locking Out on Network

[krb548]

On Friday night we experienced a problem with a lot of external network cameras on our LAN went offline.
Came into work yesterday and discovered printers would not function from our printer server.
We also discovered other TCP/IP devices on network will not function.
You can ping them and get response but software will not connect to these devices.
Re-booted main server switch in server room then mail server stopped being contactable.
It could not ping anyone or receive pings from anyone else. Put mailservers lan card onto dhcp adressing and it got an ip address but still cannot ping or be pinged.
Ended up adding new LAN card to mail server and assigned that a static IP and can now be pinged and send pings. Mail in flowing internally.

But we still appear to have issues around our site with TCP/IP. Some devices work and others dont.
An example would be that if a network printer has a LAN connection & direct connetion to local pc. Local pc cannot printer direct to printer until lan cable is removed.

We have tryed all sorts of things, disconnectiing fibre links, turning switches off etc, but still parts of network apper to be broken.

Can anyone offer any other suggestions??
Please help we are scratching already bald heads and losing more hair trying to resolve this one.
It's as if there is a faulty device on the LAN but don't know how to find it!

[DaveP]

Is there any detail about your network that you may have missed?

For example: Do you have VLANs installed? If yes is it just one of these VLANs which is giving the problem?

Other ideas anyone?

[SYNACK]

Do a network capture on your network using wireshark and see what kind of traffic is floating around. As it is site wide it very well be a faulty device or looped back cable flooding the network which will show up as a ton of rubbish traffic or broadcasts. It could also be your switch itself, if it is faulty then all network traffic is suseptable.

[krb548]

We do not have any vlans setup on the network.

Looking like it may we the switch at the core of our network which we replaced 3 years ago to a new HP chassis solution.

Talking to HP at moment to see if we are correct.
We take a printer and plug it in to another switch away from chassis and all is ok. Plug port back into chassis then printer errors.