pkspxy - The PKS proxy server

pkspxy [-d] [-o] [-c] [-F config-file]

The PKS proxy server is a caching proxy server which can be used together with PGP key servers such as pks.

The server listens to a certain port on the local system (by default port 11372, as opposed to port 11371 which is used by pks). It expects HTTP queries for URIs of the following form:

...?op=get&search=key-id&x-time=timestamp

The x-time parameter is optional; its value is a time stamp in standard Unix time format (see time(2)) in decimal representation. If it is given, the server will only transfer data when it was gathered more recently than the timestamp given. When there is no data to transfer, the server will use a 204 HTTP return code.

The proxy server operates in two different modi. By default, it starts up in online mode. In this mode, the server will immediately try to gather data if it considers this necessary. In offline mode, the server will exclusively rely on the material contained in its cache, and add requests to a queue of postponed queries. Data gathering for postponed requests is tried after configurable intervals of time when in online mode.

Data gathering happens as follows: The proxy first checks whether there are already data for the query in question. If this is the case, it further checks if these data are older than a configurable amount of time. If this is the case, it will ask the key servers which are known to it. This process will stop with the first key server which responds with actual key material.

Switching between modes can be done at run-time: When pkspxy receives a SIGUSR1 signal, it will switch to online mode and immediately process the postponed queue. When it receives SIGUSR2, the server switches to offline mode.

Upon receiving a SIGTERM, SIGINT or SIGQUIT signal, the proxy will dump the postponed queue to a file in the spool area and exit. The file generated this way is automatically read when the server gets up.

-d

Enable debug mode. This option may occur several times; expect more changes to behaviour the more often you use it. When this option is given, pkspxy will not detach itself from the current terminal.

-o

Start up in offline mode.

-c

Create the spool area. When this option is given, pkspxy will create the directories it requires for proper operation.

-F config-file

Read config-file. This parameter must be present at least once. See pkspxy.conf(5) for more information on the configuration file.

/var/cache/pkspxy/

This directory is the spool area's default location. Note that each file in the spool area represents a response for a certain query. You may use standard Unix tools to expire old data files from the spool; pkspxy is supposed to smoothly deal with files in the spool area disappearing under its feet.

/var/cache/pkspxy/pkspxy.postponed

This file is by default used for the persistent list of postponed queries. It's a simple text file, with one query string per line.

pkspxyc(1), pkspxy.conf(5), pks-intro(8), pks(8), time(2), signal(7), find(1), rm(1)

Thomas Roessler <roessler@guug.de>