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We have setup ipsec and l2tp on linux. One question came up (due to firewall management policy) is whether it's possible to have 1 virtual interface instead of one per connected client.
Now we have:
ppp0 serverip clientip1
ppp1 serverip clientip2

Want to have:
l2tp_tun serverip serverip
like with OpenVPN's tun interfaces and then to be able to push IP address and route to each client.

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I am not particularly familiar with OpenVPN or if this is what you are trying to acheive, but would it not be possible to offer a ppp ip address assignment using pppd on the other end? – Matthew Ife Nov 25 '11 at 0:37
it seems as long as we have to use ppp with l2tp stack we are forced with 1 virtual interface per connection – Alex Nov 25 '11 at 4:05
Yeah but PPPD allows you to assign the ppp endpoint a particular IP address, so you can setup ip address assignment in pppd. – Matthew Ife Nov 25 '11 at 7:43
as I said in the main question: we need 1 interface on server-side but PPPD seems to create a new interface for every new connection – Alex Nov 25 '11 at 8:02
up vote 2 down vote accepted

You can use the interface name ppp+ in iptables rules to match all interfaces starting with the name ppp. This ought to suit your needs.

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not quite what is needed but it will have to do the trick. will it also match, say, ppp15? – Alex Dec 9 '11 at 10:34
Yes, ppp15 starts with ppp. – MikeyB Dec 9 '11 at 16:53

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