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how can i configure asynchronous ppp connection on a lan so that ppp connection to ISP is made (the Internet) only when there is a request from a local net to and disconnect if there is no activity for 15 min. or more connect to the out side world how can i configure my local net so that i will be able to save bandwidth and ... . assuming i am having a gateway running linuxOS

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you have two options you can pass to pppd daemon: demand and idle. with the first option when pppd starts the ppp interface will be created but no real connection will be made until first datagram is sent. with the second option you can specify how many seconds the connection may be kept idle (that is, no traffic passing thru) until the device will be disconnected.

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can you explain your answer , i mean first assume i will have windows and and other OS's on the lan and have a single linux machine as gateway second how do i even connect to the ppp daemon from the lan hosts and more if you can plz and thank you – jspeshu Oct 15 '10 at 8:31
ppp is your wan connection on the linux router. you will have your default route up on the router through ppp when the daemon starts. lan members should get their default route and ip addresses from a dhcp service you want to (probably) host on the same linux router. for routing the lan members outside implement NAT with iptables for the network segment managed with dhcp. – sysfault Oct 15 '10 at 11:05
i still didn't get it i know the basics but your answer is not clear srry i wish i had a reputation to deduct from your ... – jspeshu Oct 15 '10 at 12:06
your local net will get on the internet through your linux router. ppp will be running on your linux router. your linux router will configure your lan clients automatically via DHCP service. your linux router will NAT your clients out thru ppp. demand/idle ppp options will answer your initial question. there are lots of ppp+nat howtos on the internet that may explain better that part. you can probably adopt to some extent this howto: – sysfault Oct 15 '10 at 12:38

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