I have a network for a small company that has been running without an issue for a few years. We have Cisco IP phones on VLAN 100 and computers on VLAN 1. The VLANS are auto assigned by the Cisco managed switch (It detects the phones and sets them to the corresponding VLAN).
We have recently added a new work area to the company where a 24 port Netgear JGS524PE switch with VLAN support has been placed. I have the managed switch connected directly to the 24 port switch (to the same port as when everything used to work without an issue). When we first set it up, there were issues with computers intermittently not being able to obtain IP addresses from the DHCP server etc. I found out that the guy that made up the cables had not crimped many of them properly and some wires were not touching the contacts etc.
After fixing that, the computers work MOST of the time now. However, I have been testing it with another computer directly connected to the 24 port switch. I found that I was only able to obtain an IP address some of the time. So I set my computer to have a static IP address. When I try to ping the upstream managed switch, sometimes I am able to ping it and other times I am not able to. I can ALWAYS ping other devices connected to the 24 port switch however. When my computer is unable to ping the managed switch, the other computers are still able to communicated across it somehow.
I am not very experienced with setting up networks (as my day job is Software Development) and so I have never encountered this type of issue.
What could be causing computers intermittently not being able to get across to the upstream switch?
Possible causes that I can think of (but unsure of the likelihood) are:
- The VLANs are somehow causing an issue. (But would this stop me from pinging the managed switch?)
- There is still a bad network cable on one of the ports that is somehow confusing the 24 port switch. (Not sure if this actually can happen or not).
- The 24 port switch is faulty. (Even though it is brand new)
- Another device on the network is causing an issue that prevents other computers from communicating properly. (Not sure if this actually can happen or not).
- I have to set something extra up on the 24 port switch. (I only just found out that it actually can be managed via a web page).