Intermittent network dropouts – duplicate ip addresses allocated ?

A client called looking for urgent advice. One user – a fashion designer was having her network connection dropped every ten or fifteen minutes. Having the network cable ruled out this left the network card suspect but I noted that during an attempt to remotely access the machine – as had been done successfully before – an unexpected message was received.

Attending site and exploring the log file showed that the problem had occurred approximately two weeks before on a Monday morning. The users were quizzed as to had any new pcs or printers been added to the network since the error showed a duplicate ip address conflict. Changing the address to a new unused ip address cured the disconnections and then the penny dropped with users – three new HTC Desire handsets had been added to the network and whilst these gained DHCP addresses from a router – the user having the problem had a static IP address in the DHCP scope range. The new devices had been allocated addresses and one of them was the same as the users pc – hence the strange message on trying to connect.

So the moral – make sure static IP addresses and dhcp scopes stay well apart.