opennhrp

OpenNHRP implements NBMA Next Hop Resolution Protocol (as defined in RFC 2332). It makes it possible to create dynamic multipoint VPN Linux router using NHRP, GRE and IPsec. It aims to be Cisco DMVPN compatible.

from https://sourceforge.net/projects/opennhrp/

https://sourceforge.net/projects/opennhrp/files/opennhrp/

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VyOS version of OpenNHRP.

OpenNHRP Release Notes

OpenNHRP is an NHRP implementation for Linux. It has most of the RFC2332
and Cisco IOS extensions.

Project homepage: http://sourceforge.net/projects/opennhrp

Git repository: git://opennhrp.git.sourceforge.net/gitroot/opennhrp


OpenNHRP embeds libev. libev is dual licensed with 2-clause BSD and
GPLv2+ licenses. See libev/LICENSE for additional details.

OpenNHRP links to c-ares. c-ares is licensed under the MIT License.


	KERNEL REQUIREMENTS

You need a kernel with ip_gre patched to support sending and receiving
using NBMA address. 

The support was originally added to 2.6.24-rc2, but it contains a bug
that prevents NAT detection. The latest fix is present in 2.6.24-rc7.

Gentoo kernels: gentoo-sources-2.6.23-r1 and gentoo-sources-2.6.22-r10
have the partitial support too (no NAT there either).

For the brave who compile their own kernels, there are patches against
vanilla 2.6.20 and 2.6.22 kernels in the patches directory. Or just
upgrade to 2.6.24 or later and no patching is required. Though, there
has been a major performance fixes in newer kernels, so 2.6.35 or later
is strongly recommended.

Also remember to turn on CONFIG_ARPD and CONFIG_NET_IPGRE in your kernel
configuration.

	SYSTEM REQUIREMENTS

To compile OpenNHRP you need:
- GNU make (3.81 or later works)
- GCC
- pkg-config
- c-ares library (Ubuntu package: libc-ares-dev)

	COMPILING

Just type 'make' and 'make install'.

	CONFIGURATION

OpenNHRP currently supports only IPv4 over IPv4 using NBMA GRE tunnels.
To create NBMA GRE tunnel you might use following:

	ip tunnel add gre1 mode gre key 1234 ttl 64
	ip addr add 10.255.255.2/24 dev gre1
	ip link set gre1 up
	
This should work with the configuration example in opennhrp.conf(5).

	IPSEC ENCRYPTION OF GRE PACKETS

ipsec-tools 0.8.0 or later is recommended. Earlier versions need patching for dmvpn to work properly.

The ipsec-tools configuration I prefer to use is: encrypt all GRE
traffic in transport mode. IPsec policy for that should be defined in
/etc/ipsec.conf:
	spdflush;
	spdadd 0.0.0.0/0 0.0.0.0/0 gre -P out ipsec esp/transport//require;
	spdadd 0.0.0.0/0 0.0.0.0/0 gre -P in  ipsec esp/transport//require;

And ipsec-tools configuration with pre-shared key could look something
like this:

/etc/racoon/racoon.conf:
	path pre_shared_key "/etc/racoon/psk.txt";
	remote anonymous {
		exchange_mode aggressive;
		lifetime time 24 hour;
		my_identifier user_fqdn "my-user-name@my-domain.example";
		nat_traversal on;
		# For ipsec-tools snapshot 2010-10-10 or later
		script "/etc/opennhrp/racoon-ph1dead.sh" phase1_dead;
		# For earlier ipsec-tools
		# script "/etc/opennhrp/racoon-ph1down.sh" phase1_down;
		proposal {
			encryption_algorithm 3des;
			hash_algorithm sha1;
			authentication_method pre_shared_key;
			dh_group 2;
		}        
	}
	sainfo anonymous {
		pfs_group 2;
		lifetime time 12 hour;
		encryption_algorithm 3des, blowfish 448, rijndael;
		authentication_algorithm hmac_sha1, hmac_md5;
		compression_algorithm deflate;
	}

And /etc/racoon/psk.txt:
	my-user-name@my-domain.example	"my-secret-pre-shared-key"

It is of course more secure to use certificates for authentication.
And using aggressive main mode is not recommended either, but it is
required to make FQDN pre-shared authentication work. This setup is
fast to do and can get you started with testing OpenNHRP.

	DOCUMENTATION

Most of the OpenNHRP documentation is in the manpages. Read them.

Also some general NHRP documents can be found from Cisco website
(www.cisco.com).

	BUGS

Use the SourceForge bug tracker or mailing list.

from  https://github.com/vyos/vyos-opennhrp