dannyboy1121:00:05:05 pppd No response to 3 echo-requests00:05:05 pppd Serial link appears to be disconnected. This is known as an LCP timeout.  pppd sends LCP echo packets, which are similar ICMP ping packets for the PPP protocol  They are sent at regular intervals set by the pppd 'lcp-echo-interval' option, and if a certain number ...

Well .. for various reasons I found that I couldn't get what I wanted out of an off the shelf firewall router ... so with some parts from ebay and a copy of smoothwall, I managed to make something that did the job and blogged it. If you're interested -  ...