xl2tpd

xl2tpd is an implementation of the Layer 2 Tunneling Protocol as defined by RFC 2661. L2TP allows you to tunnel PPP over UDP. Some ISPs use L2TP to tunnel user sessions from dial-in servers (modem banks, ADSL DSLAMs) to back-end PPP servers. Another important application is Virtual Private Networks where the IPsec protocol is used to secure the L2TP connection (L2TP/IPsec is defined by RFC 3193. xl2tpd can be used in combination with IPsec implementations such as Openswan. Example configuration files for such a setup are included in the examples directory.

xl2tpd uses a pseudo-tty to communicate with pppd. It runs in userspace but supports kernel mode L2TP.

xl2tpd supports IPsec SA Reference tracking to enable overlapping internal NAT'ed IP's by different clients (eg all clients connecting from their linksys internal IP 192.168.1.101) as well as multiple clients behind the same NAT router.

Xl2tpd is based on the L2TP code base of Jeff McAdams jeffm@iglou.com. It was de-facto maintained by Jacco de Leeuw jacco2@dds.nl in 2002 and 2003.

NOTE: In Linux kernel 4.15+ there is a kernel bug with ancillary IP_PKTINFO. As such, for Linux kernel 4.15+ we recommend the community use xl2tpd 1.3.12+

Build and install

make
sudo make install

The xl2tpd.conf(5) man page has details on how to configure xl2tpd.

Mailing Lists

https://lists.openswan.org/cgi-bin/mailman/listinfo/xl2tpd is home of the mailing list.

Note: This is a closed list - you must be subscribed to be able to post mails.

Security Vulnerability

Security vulnerabilities can be e-mailed to: security@xelerance.com