vpnc-script replacement for easy and secure split-tunnel VPN setup.
Instead of trying to copy the behavior of standard corporate VPN clients, which normally reroute all your network traffic through the VPN, this one tries to minimize your contact with an intrusive VPN. This is also known as a split-tunnel VPN, since it splits your traffic between the VPN tunnel and your normal network interfaces.
The purpose of this tool is almost the opposite; it makes it easy to connect to a VPN while minimizing the traffic that passes over the VPN.
This is for people who have to connect to the high-security VPNs of corporations or other bureaucracies (which monitor and filter and otherwise impede network traffic), and thus wish to route as little traffic as possible through those VPNs.
For example:
or
Notice that
There are many command-line options to alter the behavior of
Running with
相关帖子：https://briteming.blogspot.com/2019/10/mac-split-tunnel-vpn.html
Table of Contents
Introduction
This is a replacement for thevpnc-script
used by OpenConnect or
VPNC.Instead of trying to copy the behavior of standard corporate VPN clients, which normally reroute all your network traffic through the VPN, this one tries to minimize your contact with an intrusive VPN. This is also known as a split-tunnel VPN, since it splits your traffic between the VPN tunnel and your normal network interfaces.
vpn-slice makes it easy to set up a split-tunnel VPN:- It only routes traffic for specific hosts or subnets through the VPN.
- It automatically looks up named hosts, using the VPN's DNS servers,
and adds entries for them to your
/etc/hosts(which it cleans up after VPN disconnection), however it does not otherwise alter your/etc/resolv.confat all.
Who this is for
If you are using a VPN to route all your traffic for privacy reasons (or to avoid censorship in repressive countries), then you do not want to use this.The purpose of this tool is almost the opposite; it makes it easy to connect to a VPN while minimizing the traffic that passes over the VPN.
This is for people who have to connect to the high-security VPNs of corporations or other bureaucracies (which monitor and filter and otherwise impede network traffic), and thus wish to route as little traffic as possible through those VPNs.
Requirements
- Python 3.3+
dig(DNS lookup tool; tested with v9.9.5)- Supported OSes:
pip (make sure you are using
the Python 3.x version, usually invoked with pip3):$ pip3 install https://github.com/dlenski/vpn-slice/archive/master.zip
Usage
You should specifyvpn-slice as your connection script with
openconnect or vpnc. It has been tested with vpnc v0.5.3, OpenConnect
v7.06+ (Cisco AnyConnect and Juniper protocols) and v8.0+ (PAN GlobalProtect
protocol).For example:
$ sudo openconnect gateway.bigcorp.com -u user1234 \
-s 'vpn-slice 192.168.1.0/24 hostname1 alias2=alias2.bigcorp.com=192.168.1.43'
$ cat /etc/hosts
...
192.168.1.1 dns0.tun0 # vpn-slice-tun0 AUTOCREATED
192.168.1.2 dns1.tun0 # vpn-slice-tun0 AUTOCREATED
192.168.1.57 hostname1 hostname1.bigcorp.com # vpn-slice-tun0 AUTOCREATED
192.168.1.43 alias2 alias2.bigcorp.com # vpn-slice-tun0 AUTOCREATED
# With most versions of vpnc, you *must* specify an absolute path
# for the disconnect hook to work correctly, due to a bug.
#
# I reported this bug, but the original maintainers no longer maintain vpnc.
# https://lists.unix-ag.uni-kl.de/pipermail/vpnc-devel/2016-August/004199.html
#
# However, some Linux distro packagers have picked up my patch in recent
# releases, e.g. Ubuntu 17.04:
# https://changelogs.ubuntu.com/changelogs/pool/universe/v/vpnc/vpnc_0.5.3r550-3/changelog
#
$ sudo vpnc config_file \
--script '/path/to/vpn-slice 192.168.1.0/24 hostname1 alias2=alias2.bigcorp.com=192.168.1.43'
vpn-slice accepts both hostnames alone (hostname1) as well as
host-to-IP* aliases (alias2=alias2.bigcorp.com=192.168.1.43). The former are first looked up using the
VPN's DNS servers. Both are also added to the routing table, as well as to
/etc/hosts (unless --no-host-names is specified). As in this
example, multiple aliases can be specified for a single IP address.There are many command-line options to alter the behavior of
vpn-slice; try vpn-slice --help to show them all.Running with
--verbose makes it explain what it is doing, while running with
--dump shows the environment variables passed in by the caller.Inspiration and credits
- @jagtesh's
split-tunnelling tutorial gist taught me the
basics of how to set up a split-tunnel VPN by wrapping the standard
vpnc-script. - @apenwarr's
sshuttle has the excellent
--auto-hostsand--seed-hostsoptions. These inspired the automatic host lookup feature. - @gmacon's PR #11 substantially refactored the code to separate the OS-dependent parts more cleanly, and added macOS support.
相关帖子：https://briteming.blogspot.com/2019/10/mac-split-tunnel-vpn.html
