stud is a network proxy that terminates TLS/SSL connections and forwards the unencrypted traffic to some backend. It's designed to handle 10s of thousands of connections efficiently on multicore machines.
stud has very few features -- it's designed to be paired with an intelligent backend like haproxy or nginx. It maintains a strict 1:1 connection pattern with this backend handler so that the backend can dictate throttling behavior, maxmium connection behavior, availability of service, etc.
The only required argument is a path to a PEM file that contains the certificate (or a chain of certificates) and private key. It should also contain DH parameter if you wish to use Diffie-Hellman cipher suites.
The options are as follows:
Use TLSv1 (default).
Use only SSLv3 and no TLSv1.
- -c ciphers
Set allowed ciphers using the same format as
openssl ciphers. For example, you can use RSA:!COMPLEMENTOFALL.
- -e engine
Specify an OpenSSL engine by its unique ID. The engine will be used by default for all algorithms. The keyword auto can be used to load all available engines.
- -b host,port
Define backend. Default is 127.0.0.1,8000. Incoming connections will be unwrapped and sent to this IP and port.
- -f host,port
Define frontend. Default is *,8443. Incoming connections will be accepted to this IP and port and will be sent to the backend defined above.
- -n cores
Use cores worker processes. Default is 1.
- -B backlog
Set listen backlog size. Default is 100.
- -C cache
Set shared cache size in sessions. By default, no shared cache is used.
- -r path
Chroot to the given path. By default, no chroot is done.
- -u username
Set GID/UID after binding the socket. By default, no privilege is dropped.
Be quiet. Only emit error messages.
Send messages to syslog in addition to stderr and stdout.
- --syslog-facility facility
Syslog facility to use. Default is daemon.
Write 1 octet with the IP family followed by the IP address in 4 (IPv4) or 16 (IPv6) octets little-endian to backend before the actual data.
Write HaProxy's PROXY (IPv4 or IPv6) protocol line before actual data.
ciphers(1SSL), dhparam(1SSL), haproxy(1)
stud was originally written by Jamie Turner (@jamwt) and is maintained by the Bump server team. It currently provides server-side TLS termination for over 40 million Bump users.