jail 1.6

jail (Just Another IP Logger) is a simple, but often useful network security tool which displays ICMP packets and attempted TCP connections from remote hosts.

The application features better configuration and logging options than the iplogger package it was written to replace.

icmplog and tcplog can either ignore any packet, or log it at any of the
syslog levels (as defined in < syslog.h >). The log level is configurable
depending on the ICMP type (icmplog) or the port on which a connection is
requested (tcplog). The default facility (LOG_DAEMON) for logging messages
can also be changed in the configurations files.

The level at which a given type of packet is logged is specified in the
configuration files (/etc/icmplog.conf and /etc/tcplog.conf by default,
which can be overriden with the --file option). You can also specify
a default level, which matches packets that have an unknown or unconfigured
type. See the example configurations included and the icmplog(8) and
tcplog(8) manual pages for more information.

Log entries contain the source and type (icmplog) or destination port
(tcplog) of the received packet. If a packet is of an unknown type, its
numeric value is logged instead of its name. The source is logged
either as a hostname or as an IP address (see the -n option). Typical
entries look like:

Jun 16 17:47:30 lustre icmplog: started
Jun 16 17:47:31 lustre tcplog: started
Jun 16 18:54:14 lustre icmplog: time exceeded from sunsite.unc.edu
Jun 16 18:56:14 lustre tcplog: port 1039 request from ftp.cs.umn.edu
Jun 16 19:47:24 lustre icmplog: destination unreachable from 209.39.121.4

The INSTALL file contains detailed installation instructions. Read the
icmplog(8), icmplog.conf(5), tcplog(8) and tcplog.conf(5) manual pages, and
the example configuration files (icmplog.conf and tcplog.conf) for
more information on setting up and using jail.

jail was originally based on the iplogger package, but offers greater
configurability and better options. It bears very little resemblance to
the original program now.

jail is distributed under the Artistic License (a copy of which is included
in the distribution) and comes with no warranty, express or implied. If it
breaks...well, keep the pieces.