Comments on: How to create IPv4 GRE tunnels in Ubuntu http://onvox.net/linux/how-to-create-ipv4-gre-tunnels-in-ubuntu Thu, 10 May 2012 14:14:57 +0000 hourly 1 http://wordpress.org/?v=3.3.2 By: Webberist http://onvox.net/linux/how-to-create-ipv4-gre-tunnels-in-ubuntu/comment-page-1#comment-32 Webberist Thu, 10 May 2012 14:14:57 +0000 http://onvox.net/?p=94#comment-32 With recent releases of Ubuntu (tested on 12.04 LTS server) the /etc/network/interfaces file is used to establish GRE tunnels. See the man page for interfaces at http://manpages.ubuntu.com/manpages/precise/man5/interfaces.5.html This example config works for a local LAN on 10.0.0.0/24 from this Ubuntu computer at 10.0.0.20 to a router at 10.0.0.1. The local tunneled endpoint IP is 172.16.16.2 and the remote endpoint IP is 172.16.16.1. This config isn't very useful as is but it demonstrates a working tunnel in a simple LAN setup. <pre> auto gre1 iface gre1 inet tunnel address 172.16.16.2 mode gre endpoint 10.0.0.1 dstaddr 172.16.16.1 local 10.0.0.20 ttl 255 netmask 255.255.255.252 </pre> If you get a message along the lines of ioalloc buffer full it's because the tunnel interface has already been created. You can see and delete the interfaces with iptunnel. Easiest option is to reboot or use a different tunnel interface as sometimes it won't delete. -Webberist With recent releases of Ubuntu (tested on 12.04 LTS server) the /etc/network/interfaces file is used to establish GRE tunnels. See the man page for interfaces at http://manpages.ubuntu.com/manpages/precise/man5/interfaces.5.html
This example config works for a local LAN on 10.0.0.0/24 from this Ubuntu computer at 10.0.0.20 to a router at 10.0.0.1. The local tunneled endpoint IP is 172.16.16.2 and the remote endpoint IP is 172.16.16.1. This config isn’t very useful as is but it demonstrates a working tunnel in a simple LAN setup.

auto gre1
iface gre1 inet tunnel
        address 172.16.16.2
        mode gre
        endpoint 10.0.0.1
        dstaddr 172.16.16.1
        local 10.0.0.20
        ttl 255
        netmask 255.255.255.252

If you get a message along the lines of ioalloc buffer full it’s because the tunnel interface has already been created. You can see and delete the interfaces with iptunnel. Easiest option is to reboot or use a different tunnel interface as sometimes it won’t delete.

-Webberist

]]> By: Quora http://onvox.net/linux/how-to-create-ipv4-gre-tunnels-in-ubuntu/comment-page-1#comment-20 Quora Mon, 12 Sep 2011 21:17:29 +0000 http://onvox.net/?p=94#comment-20 <strong>What Saas or Free/Opensource SSL VPN solutions are available that connect cloud servers and local area network servers/desktops?...</strong> Also check out this article on setting up GRE tunnels in Ubuntu http://onvox.net/linux/how-to-create-ipv4-gre-tunnels-in-ubuntu... What Saas or Free/Opensource SSL VPN solutions are available that connect cloud servers and local area network servers/desktops?…

Also check out this article on setting up GRE tunnels in Ubuntu http://onvox.net/linux/how-to-create-ipv4-gre-tunnels-in-ubuntu…

]]> By: GRE Tunnel | wiki'ed http://onvox.net/linux/how-to-create-ipv4-gre-tunnels-in-ubuntu/comment-page-1#comment-17 GRE Tunnel | wiki'ed Wed, 19 Jan 2011 20:33:43 +0000 http://onvox.net/?p=94#comment-17 [...] GRE tunnels can incapsulate IPv4/IPv6 unicast/multicast traffic, so it is de-facto tunnel standard for dynamic routed networks. You can setup up to 64K tunnels for an unique tunnel endpoints pair. It can work with FreeBSD and cisco IOS. Kernel module is ‘ip_gre’. Server_1 $ modprobe ip_gre $ ip tunnel add gre1 mode gre local 10.20.30.40 remote 50.60.70.80 $ ip address add dev gre1 192.168.1.2 peer 192.168.1.1/30 $ ip link set dev gre1 up $ ip route add 172.16.10.0/24 via 192.168.1.1 $ ip link show gre1 $ ifconfig gre1 Server_2 $ modprobe ip_gre $ ip tunnel add gre1 mode gre local 50.60.70.80 remote 10.20.30.40 $ ip address add dev gre1 192.168.1.1 peer 192.168.1.2/30 $ ip link set dev gre1 up $ ip route add 172.16.20.0/24 via 192.168.1.2 $ ip link show gre1 $ ifconfig gre1 $ ping 192.168.1.2 PING 192.168.1.2 (192.168.1.2) 56(84) bytes of data. 64 bytes from 192.168.1.2: icmp_seq=1 ttl=64 time=201 ms $ ip tunnel del gre1 $ rmmod ip_gre Ubuntu: http://onvox.net/linux/how-to-create-ipv4-gre-tunnels-in-ubuntu [...] [...] GRE tunnels can incapsulate IPv4/IPv6 unicast/multicast traffic, so it is de-facto tunnel standard for dynamic routed networks. You can setup up to 64K tunnels for an unique tunnel endpoints pair. It can work with FreeBSD and cisco IOS. Kernel module is ‘ip_gre’. Server_1 $ modprobe ip_gre $ ip tunnel add gre1 mode gre local 10.20.30.40 remote 50.60.70.80 $ ip address add dev gre1 192.168.1.2 peer 192.168.1.1/30 $ ip link set dev gre1 up $ ip route add 172.16.10.0/24 via 192.168.1.1 $ ip link show gre1 $ ifconfig gre1 Server_2 $ modprobe ip_gre $ ip tunnel add gre1 mode gre local 50.60.70.80 remote 10.20.30.40 $ ip address add dev gre1 192.168.1.1 peer 192.168.1.2/30 $ ip link set dev gre1 up $ ip route add 172.16.20.0/24 via 192.168.1.2 $ ip link show gre1 $ ifconfig gre1 $ ping 192.168.1.2 PING 192.168.1.2 (192.168.1.2) 56(84) bytes of data. 64 bytes from 192.168.1.2: icmp_seq=1 ttl=64 time=201 ms $ ip tunnel del gre1 $ rmmod ip_gre Ubuntu: http://onvox.net/linux/how-to-create-ipv4-gre-tunnels-in-ubuntu [...]

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