In reply to a post by RLG:

No internet connection. Point to point test is fine.

Point to point testing at what level?

Do you mean with your cable tester (which is mainly the physical level)?
Or perhaps the ethernet level (layer 2)? Perhaps best seen by the LEDs associated with each port lighting up (though I'm guessing at that)
Or perhaps it is working just above the ethernet level - so perhaps the ARP protocol works?
Or perhaps is is working at layer 3 - where ICMP pings work successfully.

I suspect you mean your cable tester alone.

I can't help but think that your testing starts with a layer 1 test, and then jumps to assume that all the intermediate layers are working, before concluding that access to the internet is not working - by running an application at layer 7.

I think you need to start checking the lower layers of the LAN before worrying about routing out onto the WAN.

As you've jumped to having large ethernet switches, you've probably outgrown any home or SOHO solutions. The switches you have might, for example, have included VLAN functionality, where not all ports are meant to be switchable to all other ports. Or perhaps the auto-negotiation for 10/100 speeds and half/full duplex has not worked.

Or perhaps you are hitting a problem with the switch as you move your laptop from port to port - that it remembers your MAC address wrongly, and directs traffic down to an old port.

Perhaps you are relying on a faulty DHCP server at the IP layer, and the PC isn't being given an IP address properly. Perhaps this is interacting badly with ARP caching in the switch.

I suspect that you will need to check the intermediate layers with ARP and PING commands, while keeping a fixed IP address for the PC. You might even need a second PC.

I appreciate the time to post this! I think this may be a job for someone who is far more advanced in this field than myself.

Personally I think it was unfair of whoever roped you in to doing this by expecting you to install data networks when you don't have the training, experience or necessary equipment.

Data networks have some very specific requirements and even experts still need the right test equipment to make sure the cables are working correctly. Data networks are less tolerant of problems than many other cabling systems.

In reply to a post by ian72:

Personally I think it was unfair of whoever roped you in to doing this by expecting you to install data networks when you don't have the training, experience or necessary equipment.

That is true, although installing the cable, checking continuity and pairs is a reasonable expectation. Going beyond that when there is an issue is definitely taking the .... And we have seen from the posts that the OP has a reasonable understanding of the cabling methodology and could have done a good job.

Morning RLG

MHC advised-
"
What about getting a patch lead and cutting it in half. Then strip the wires back and connect 1-2, 3-4, 5-6, 7-8. Plug that in at the remote end. Use the other half at the patch panel and use a meter to check the continuity/resistance between 1&2, 3&4, 5&5, 7&8.
"

Basically I tested cables in the same way; but with the addition of also checking across pairs, to ensure that there were no Shorts of that nature-

Pair 1&2 to the other three etc

It should not happen; but occasionally I found that it did, particularly when anyone inexperienced in such connectors had done the work.

The fault was generally not in the crimped/trapped part; but immediately behind at the insulation, where if stranded, the odd strand would be physically short, stick out and make contact with the adjacent lead - I'm sure you have come across this in your main work.

Difficult to spot and even worse if intermittent.

As you will know from your own experience, one has to be systematic and pedantic, when doing such work, both the actual connecting/crimping etc; and the subsequent testing.

Yes you are definitely spot on there! I am leaving this job because I seem to get lumbered with stuff that I have never done before and then they wonder why it doesn't work as expected.

I came on board to run the fire and security side of the business, I'm even involved in sorting out a Legrand home entertainment system which was installed 3 years ago and was never running as it was sold. Which I'm glad to say is almost done.

I'll be on site today to go through all of these suggestions and I will keep you posted, especially if I find the solution. Most of the time it's something quite simple.

Thank you all for your advice!