Free easy to port software for linux

RetroForth is a compact, open source Forth development system. RetroForth can be used under FreeBSD, Linux, BeOS, Windows, SCO OpenServer, or as an operating system.
It is easy very easy to learn, use, and extend with standard libraries like SDL, and it can also be used to create tight, stand-alone applications.
Main features:
- Small: Size RetroForth was designed to be a small Forth. As such, the source code is about 20 kilobytes in size, and most binaries take about 5 kilobytes.
- Portable: Despite being written in assembly language, RetroForth is very easy to port to new operating systems. As noted elsewhere, it runs on at least five major operating systems, and can be used as an OS. Thanks to optional use of libc, many other x86 operating systems should be able to use RetroForth with nothing more than a recompile of the source.
- Simplicity: A major aspect of our design philosophy is simplicity. We have designed RetroForth to be easy to learn and use, while not sacrificing its usefulness.
- Documentation: We provide a manual with every recent release. This is included in ASCII text and NoteBook formats. Other formats, including HTML, PDF, and PostScript will be supported in the near future.
- Support: Options We try to help developers using RetroForth as much as possible. We provide a Forum, Wiki, IRC channel, and a mailing list. Were quite willing to answer questions and listen to suggestions

Bash Port Knocking is a set of scripts that use standard Linux tools to acheive a port knocking system. A Web page is used to open ports, and an email is sent every time the port knocking sequence is successfully made.
Main features:
- Uses custom scripts to begin firewall and ipmasquerade for multiple connections. This can be used as a gateway for ethernet provided Internet Connectivity in addition to supplying port knocking services.
- This script creates a web page that can be used for port knocking. This page can be used locally if the browser is using a public/anonymous proxy.
- This scripts emails the above created browser page to a specified email recipient each time the port knock sequence is successfully acheived.
- This script logs successful port knocks but denies knocks that hit a port designed in the initial scripts. This allows the script to be closed automatically if someone is hitting your computer repeatedly trying to automatically open the ports and allows you to close the ports if youve completed a log in or other desired action.
- In its current state it has run successfully for quite some time and been tested repeatedly with both anonymous proxy and remotely by the author for opening ssh.
- It allows the user to control the depth of the logs searched to function in a very low usage enviornment or a very high use enviornment as desired.
- It sorts the knocks by knocking address to prevent possible denial of service.

Active port forwarder is a software tool for secure port forwarding. Active port forwarder uses SSL to increase security of communication between a server and a client. Originally, it was developed to forward data point to point.
However, the need for bypassing firewalls in order to connect to internally located computers influenced the further development of the project.
AF is dedicated for people, who dont have an external ip number and want to make some services available across the net.
Moreover, zlib is used to compress the transferred data.
Using one, permanent data/control channel with flow control / packet buffering provides good performance and reasonably small latency.
Running afserver does not require root priviledges, nor does it use threads or other processes.
Enhancements:
- The bug in the ip_listen function (visible on the systems without IPv6 support) has been fixed.

Tennix! SDL Port is a simple two-player tennis game.

It features simple image loading (with all game graphics being customizable by simply editing them with a graphics editor like The GIMP), sound effects, stadium audience sounds, and ball shadows.

The source code for this SDL port is released under the terms of the GNU General Public License, Version 2 (or later).

Controls

Player 1 uses the keys W, S and D and Player 2 uses O, L and K.

Really Slick ScreenSavers GLX Port is a port of some nifty OpenGL screensavers that were originally written for Windows to GLX.
Really Slick ScreenSavers GLX Port is intended for use with an existing screensaver daemon like xscreensaver.
Enhancements:
- This release fixes minor bugs exposed by newer compilers and libraries.

Parallel Port Make project is a tool to build FreeBSD ports in parallel to fully take advantage of modern multi-core and processor machines.

Default: pportmake.py --clean -- cleanup --install -job=2 [port1] [portn]

Example: pportmake.py irc/irssi irc/epic

Advanced: pportmake.py -rSvD -j 10 irc/irssi

-h --help Show this help usage message
-c --clean Clean port before compiling
-C --cleanup Clean port after compiling
-d --deinstall Deinstall ports, implied by reinstall
-f --force Force a port and all dependancies to be installed
-G --noconfig Dont recursively configure options
-i --install Install port (default)
-j n --jobs=n Number of threads to use, 1 or 2 per CPU core
is recommended
Default is 2
-O args --options=foo List of arguments to pass to make.
E.g. -O -DX11=yes -DFOO
-r --reinstall Reinstall port and ALL dependancies
-S --maxspeed Try and speed up by maximising CPU usuage.
This may break some ports, use with caution
-w --noclean Dont make clean before compiling
-W --nocleanup Dont make clean after compiling
-v --verbose Be extra verbose
-V --version Show version information
-D --debug Show some debugging info
-P --pretend Dont actually alter the ports

NOTES: It is currently only safe to run 1 copy of this and not have other ports compiling simultaneously

NAT and blocking all but Port 22 is a simple iptables firewall script.

Sample:

# Internal and External Devices
dev_world=ppp0
dev_int=eth0

# Firewall IP
addr_int=192.168.1.1

# Internal Net
net_int=192.168.1.0/24

###################################################
# Load Modules
insmod ip_tables
insmod ip_conntrack
insmod ip_conntrack_ftp
insmod ipt_state
insmod iptable_nat
insmod ipt_MASQUERADE

###################################################
# Delete all Rules in Filtertable
iptables -F

###################################################
# Define new chains
iptables -N BLOCK
iptables -N EXT-INT
iptables -N INT-EXT
iptables -N ICMP-DENY
iptables -N INT-IF
iptables -N EXT-IF

###################################################

iptables -A BLOCK -m state --state ESTABLISHED,RELATED -j ACCEPT
iptables -A BLOCK -m state --state NEW -i ! $dev_world -j ACCEPT
iptables -A BLOCK -j DROP

iptables -A INPUT -j BLOCK
iptables -A FORWARD -j BLOCK

###################################################
# Point to chains
iptables -A INPUT -i lo -j ACCEPT
iptables -A INPUT -i $dev_int -s $net_int -j INT-IF
iptables -A INPUT -d ! $addr_int -i $dev_world -s ! $net_int -j EXT-IF
iptables -A INPUT -j DROP

iptables -A FORWARD -d ! $net_int -i $dev_world -s $net_int -j INT-EXT
iptables -A FORWARD -d $net_int -i $dev_int -s ! $net_int -j EXT-INT
iptables -A FORWARD -j DROP

iptables -A OUTPUT -j ACCEPT

###################################################
# Chain Rules
iptables -A EXT-INT -j DROP

iptables -A EXT-IF -i ! $dev_world -j DROP
iptables -A EXT-IF -p tcp --dport 22 -j ACCEPT
iptables -A EXT-IF -p tcp --dport 5901 -j ACCEPT
iptables -A EXT-IF -p tcp --dport 1024: -j ACCEPT
iptables -A EXT-IF -p udp --dport 1024: -j ACCEPT
iptables -A EXT-IF -j DROP

iptables -A INT-IF -j ACCEPT

###################################################
# NAT Rules
# Standard Routing
iptables -A POSTROUTING -t nat -o $dev_world -j MASQUERADE -s $net_int

# Port Forwarding
#iptables -A PREROUTING -t nat -p tcp -d 192.168.1.1 --dport 5901 --to 192.168.1.2:5901 -j DNAT

##################################################
# Enable IP-Forwarding
echo 1 > /proc/sys/net/ipv4/ip_forward)