Thanks for the replies
I know very little about DHCP, but these are the settings on the mac:
Configure IPv4: Using DHCP
IP Address: 192.168.1.67
Subnet Mask: 255.255.255.0
And on my router DHCP settings, I have;
192.168.1.0 / 255.255.255.0 (default) checked and all the addresses seem to match up.
As I say, its an intermittent problem. Is there any specific info I can provide which may help troubleshoot?
The modem is a 2wire 1800HG.