About

This program is openconnect VPN server (ocserv), a server for the openconnect VPN client. It is believed to be compatible with the protocol used by CISCO's AnyConnect SSL VPN.

Build dependencies

Required dependencies (Debian pkg/Fedora pkg):

libgnutls28-dev      / gnutls-devel

Optional dependencies that enable specific functionality:

TCP wrappers: libwrap0-dev       / tcp_wrappers-devel
PAM:          libpam0g-dev       / pam-devel
LZ4:          liblz4-dev         / lz4-devel
seccomp:      libseccomp-dev     / libseccomp-devel
occtl:        libreadline-dev    / readline-devel
              libnl-route-3-dev  / libnl3-devel
GSSAPI:       libkrb5-dev        / krb5-devel

Dependencies for development, or dependencies that can be skipped in an embedded system (e.g., because a replacement library is included):

libprotobuf-c0-dev / protobuf-c-devel
libtalloc-dev      / libtalloc-devel
libhttp-parser-dev / http-parser-devel
libpcl1-dev        / pcllib-devel
libopts25-dev      / autogen-libopts-devel
autogen            / autogen
protobuf-c-compiler/ protobuf-c
gperf              / gperf

See README-radius for more information on Radius dependencies and its configuration.

Build instructions

To build from a distributed release use:

$ ./configure && make

When cross compiling it may be useful to add the --enable-local-libopts option to configure.

To build from the git repository use:

$ autoreconf -fvi
$ ./configure && make

In addition to the prerequisites listed above, building from git requires the following packages: autoconf, automake, autogen, git2cl, and xz.

Note that the system's autogen version must match the included libopts version on the development system, if the included libopts library is to be used.

Installation instructions

Now you need to generate a certificate. E.g.

$ certtool --generate-privkey > ./test-key.pem
$ certtool --generate-self-signed --load-privkey test-key.pem --outfile test-cert.pem

(make sure you enable encryption or signing)

To run the server on the foreground edit the sample.config and then run:

# cd doc && ../src/ocserv -f -c sample.config

Profiling

If you use ocserv on a server with significant load and you'd like to help improve it, you may help by sending profiling information. That includes the bottlenecks in software, so future optimizations could be spent on the real needs.

In a Linux system you can profile ocserv using the following command.

# perf record -g ocserv

After the server is terminated, the output is placed in perf.data. It does not contain any sensitive information. If you run a server for long time, and under usage (i.e., clients connecting and transferring data), please send that information to nmav@gnutls.org.

You may examine the output using:

# perf report

How the VPN works

Please see the technical description page.