GS324TP becomes undiscoverable when connected to a router

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scalextrix wrote:
I am having a similar problem, my JGS524PE works, but after a short time the IP address becomes unreachable, an arp -a doesnt show it connected to the network.

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Before your computer can establish a connection by IPv4 on the LAN, it has to find the Link Layer address by doing an ARP lookup. This will add the ARP entry to the dynamic ARP list. If your local IP stack does not have any communication with the switch embedded controller over IP for a the "Reachable" time (30 sec multiplied by a random factor between 0.5 and 1.5) the ARP entry does become "stale". Before being able to connect by IP again, another ARP query must be sent. If the query isn't resolved, the connection can't be established. Further on, each IP stack has a garbage collector which is run under some conditions, e.g. the max length of the ARP table is reached, an/or on a regular schedule.

If your local computer does not have a dynamic ARP entry (by checking arp -a), this does no indication that the device is not connected on the LAN.

If at the same time the discovery utility (using the NDST protocol) can't discover the switch, this could be caused by a similar reason.

In common is that ARP and NDST are sending frames to a broadcast MAC ff:ff:ff:ff:ff:ff. If there is something prohibiting or killing this communication from the local host to the device (here the switch), things will simply not work - neither the discovery can succeed, nor the IPv4 connection can be established.

Can you define this "short time"?

Will the switch be reachable short after booting, but then after a time no longer?

What devices are in the data patch from the computer to the switch?

Does the discovery tool and web UI access work on a computer (ideally the same) when connected direct to the switch? 

More for curiosity, what is the switch controller IPv4 config (address, mask, ...)?