SNI Proxy

Proxies incoming HTTP and TLS connections based on the hostname contained in the initial request. This enables HTTPS name-based virtual hosting to separate backend servers without installing the private key on the proxy machine.

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Features

• Name-based proxying of HTTPS without decrypting traffic. No keys or certificates required.
• Supports both TLS and HTTP protocols.
• Supports IPv4, IPv6 and Unix domain sockets for both back end servers and listeners.
• Supports multiple listening sockets per instance.

Usage

Usage: sniproxy [-c <config>] [-f] [-n <max file descriptor limit>]
    -c  configuration file, defaults to /etc/sniproxy.conf
    -f  run in foreground, do not drop privileges
    -n  specify file descriptor limit

Installation

For Debian or Fedora based Linux distributions see building packages below.

Prerequisites

• Autotools (autoconf, automake, gettext and libtool)
• libev4, libpcre and libudns development headers
• Perl and cURL for test suite

Install

./autogen.sh && ./configure && make check && sudo make install

Building Debian/Ubuntu package

This is the preferred installation method on recent Debian based distributions:

1. Install required packages

   sudo apt-get install autotools-dev cdbs debhelper dh-autoreconf dpkg-dev gettext libev-dev libpcre3-dev libudns-dev pkg-config

2. Build a Debian package

   dpkg-buildpackage

3. Install the resulting package

   sudo dpkg -i ../sniproxy__.deb

Note on Upgrading

The version of sniproxy is not automatically updated after each commit, so if you are upgrading to a later version, the version number of the sniproxy package may not have actually changed. This may cause issues with the upgrade process. It is recommended you uninstall sudo apt-get remove sniproxy then reinstall the new version.

Building Fedora/RedHat package

This is the preferred installation method for modern Fedora based distributions.

1. Install required packages

    sudo yum install rpm-build autoconf automake curl libev-devel pcre-devel perl pkgconfig udns-devel
   

2. Build a distribution tarball:

    ./autogen && ./configure && make dist
   

3. Build a RPM package

    rpmbuild --define "_sourcedir `pwd`" -ba redhat/sniproxy.spec
   

4. Install resulting RPM

    sudo yum install ../sniproxy-<version>.<arch>.rpm
   

I've used Scientific Linux 6 a fair amount, but I prefer Debian based distributions. I do not test building RPMs frequently (SL6 doesn't have a libev-devel package). This build process may not follow the current Fedora packaging standards, and may not even work.

Configuration Syntax

user daemon

pidfile /tmp/sniproxy.pid

error_log {
    syslog daemon
    priority notice
}

listener 127.0.0.1:443 {
    protocol tls
    table TableName

    # Specify a server to use if the initial client request doesn't contain
    # a hostname
    fallback 192.0.2.5:443
}

table TableName {
    # Match exact request hostnames
    example.com 192.0.2.10:4343
    example.net [2001:DB8::1:10]:443
    # Or use regular expression to match
    .*\\.com    [2001:DB8::1:11]:443
    # Combining regular expression and wildcard will resolve the hostname
    # client requested and proxy to it
    .*\\.edu    *:443
}

DNS Resolution

Using hostnames or wildcard entries in the configuration requires sniproxy to be built with UDNS. SNIProxy will still build without UDNS, but these features will be unavailable.

UDNS uses a single UDP socket for all queries, so it is recommended you use a local caching DNS resolver (with a single socket each DNS query is protected by spoofing by a single 16 bit query ID, which makes it relatively easy to spoof).

UDNS is currently not available in Debian stable, but a package can be easily built from the Debian testing or Ubuntu source packages:

mkdir udns_packaging
cd udns_packaging
wget http://archive.ubuntu.com/ubuntu/pool/universe/u/udns/udns_0.4-1.dsc
wget http://archive.ubuntu.com/ubuntu/pool/universe/u/udns/udns_0.4.orig.tar.gz
wget http://archive.ubuntu.com/ubuntu/pool/universe/u/udns/udns_0.4-1.debian.tar.gz
tar xfz udns_0.4.orig.tar.gz
cd udns-0.4/
tar xfz ../udns_0.4-1.debian.tar.gz
dpkg-buildpackage
cd ..
sudo dpkg -i libudns-dev_0.4-1_amd64.deb libudns0_0.4-1_amd64.deb