Gentoo Archives: gentoo-user

From: thegeezer <thegeezer@×××××××××.net>
To: gentoo-user@l.g.o
Subject: [gentoo-user] GRE link state detection
Date: Thu, 05 Sep 2013 14:50:08
1 Howdy all,
2 i was wondering if anyone has any idea if there is a means by which i
3 can detect GRE link state ?
5 what i have is two sites each with two very unstable internet links
6 in order to vpn between them i have ipsec tunnels linking each side
7 twice (four ipsec tunnels in total)
8 i then have 4x GRE tunnels over the top of those in order that i have a
9 secured routable VPN
10 this gives me net.vpn0 net.vpn1 net.vpn2 and net.vpn3
11 finally i run BIRD over the top which works very well, and synchronises
12 routing tables between the two sites, and allows for me to do such fun as
13 # /etc/init.d/net.vpn0 stop
14 and watch all traffic automagically cut over to another link.
16 so far so awesome.
18 however, as i said the internet links are very unstable, and sometimes
19 just blackhole. so what i was hoping to do is just enable keepalives on
20 the gre tunnel. which sadly seems to be cisco only.
21 can anyone suggest a way of detecting if the GRE is not fully connected ?
22 BIRD only fails over if the net.vpn0 device is down (ifconfig up/down)
23 and for the life of me i cannot find how to detect if a GRE tunnel is
24 'connected', it seems to just blindly send packets to the remote IP.
25 is my only choice to use L2TP instead ?
27 thanks in advance for any suggestions; if anyone would like the configs
28 in order to set this up let me know and i'll reply to list with a mini-howto
29 PS if i'm on the wrong list i'd welcome a friendly push to the correct list


Subject Author
Re: [gentoo-user] GRE link state detection Mick <michaelkintzios@×××××.com>