Free tcp connections software for linux

tcptrack provides a packet sniffer that displays TCP connections similarly to top.

tcptrack is a packet sniffer, which passively watches for connections on a specified network interface, tracks their states, and lists them in a manner similar to the Unix top command.

It displays source and destination addresses and ports, connection state, idle time, and bandwidth usage.

prtunnel is a program that can tunnel TCP/IP connections in a variety of ways, including through HTTP and SOCKS5 proxy servers. Some if its possible uses include:
- Tunneling TCP connections from client programs to a remote server through an HTTP or SOCKS5 proxy (useful if youre behind such a proxy and want to use a program that doesnt have native proxy support)
- Tunneling TCP connections from SOCKS-capable client programs through an HTTP or SOCKS5 proxy
- Tunneling TCP connections from an IPv4 client program to an IPv6 server and vice-versa
- Forwarding TCP connections
- Running as a simple SOCKS proxy server
prtunnel project was developed and used under Linux and BSD-based operating systems.
Enhancements:
- A bug that would cause malloc(0) to be called in some situations (which could cause problems on some systems) has been fixed.
- The server timeout, if specified, is now set before the proxy server successfully connects to the remote server, which will prevent the program from hanging if the proxy does not respond to the client.

tcptunnel is a simple TCP tunnel written in Perl.

Also is a versatile tcp tunnel. The tcptunnel uses:
- tunnelling through a firewall or proxy
- redirecting tcp connections to other ports or machines
- debugging tcp connections in-place
- packet sniffing

The tcptunnel listens on local port < port > and when a connection is made it connects the other end of the tunnel as follows:
a) With no proxy specified, it connects the other end
to < srvport > on < srv >.
b) With a proxy, it connects to < srvport > on < proxy >.
It then directs the proxy to telnet to < srv >, and then it connects the ends of the tunnel.

Cubehub is a simple UDP over TCP tunnel application written in Java. It is designed to help people behind a firewall to connect through a TCP connection and play Quake and other UDP-based games.
SOCKS 4 and 5 are protocols that are supposed to allow users to send data through a firewall. However, they only work like this if the SOCKS server is on the firewall itself. Whilst TCP/IP traffic is frequently permitted through firewalls, UDP/IP (required by most online games) is often blocked. When a SOCKS 5 server relays UDP data (SOCKS 4 does not support UDP), the packets are simply relayed, there is no tunnelling involved.
This application provides a solution, tunnelling the data being relayed by a SOCKS server over one or (for better gaming performance) multiple TCP connections to help applications and games to work from behind a restrictive firewall.
Main features:
- Socks 4/5 server
- TCP and UDP tunnelling over single or multiple TCP connections
- Resilience against individual connection dropping

FixkaraTheme is a little SuperKaramba theme, which is for gentoo with a resolution of 1280x1024.
FixkaraTheme informs you about:
- System
- CPU
- RAM
- Disk Peformance
- TCP Connections
- and you can syncronize your ebuild with sync and can emerge the packages.

Ptunnel is an application that allows you to reliably tunnel TCP connections to a remote host using ICMP echo request and reply packets, commonly known as ping requests and replies. At first glance, this might seem like a rather useless thing to do, but it can actually come in your help in some cases.
Setting: Youre on the go, and stumble across an open wireless network. The network gives you an IP address, but wont let you send TCP or UDP packets out to the rest of the internet, for instance to check your mail. What to do? By chance, you discover that the network will allow you to ping any computer on the rest of the internet. With ptunnel, you can utilize this feature to check your mail, or do other things that require TCP.
Main features:
- Tunnel TCP using ICMP echo request and reply packets
- Connections are reliable (lost packets are resent as necessary)
- Handles multiple connections
- Acceptable bandwidth (150 kb/s downstream and about 50 kb/s upstream are the currently measured maximas for one tunnel, but with tweaking this can be improved further)
- Authentication, to prevent just anyone from using your proxy

linux-identd is a user identification daemon for Linux, which implements the Identification Protocol (RFC1413). This protocol is used to identify active TCP connections.
The daemon listens to TCP port 113 (auth) and can be run either as a stand-alone daemon or through inetd(8). This program is licensed through the GNU General Public License.
Installation:
To compile and install this program:
$ make
$ make install
To start identd in daemon mode:
$ /usr/sbin/identd -d
To start identd through inetd add the following line to /etc/inetd.conf:
auth stream tcp nowait nobody /usr/sbin/in.identd in.identd
Thats it!
Enhancements:
- Added option -l to log connections.
- Fixed a sizeof() bug.
- Fixed spelling error.
- Updated man page.
- Minor Makefile cleanups.

Cutter is an TCP/IP Connection cutting on Linux Firewalls and Routers.

Cutter is an open source program that uses the FIN-ACK-RST packet technique described above to abort TCP/IP connections routed over the firewall or router on which it is run. It can be called using one of the following four syntaxes.

cutter ip-address

Example: "cutter 10.10.0.45"

Cuts all connections passing through the firewall between any ports on the specified ip-address (either a "private" or "public" address) and any other hosts. This can be used to close down all incoming connections to a particular server, all outgoing connections from a particular client or all outgoing connections to a server.

cutter ip-address port

Example: "cutter 200.1.2.3 80"

Cuts all connections to or from the specified ip-address/port pair. This allows the user to be a little more specific than the previous example and allows targetting of specific services on specific hosts.

cutter ip-address-1 port-1 ip-address-2

Example "cutter 200.1.2.3 22 10.10.0.45"

Cuts all connections between ip-address-2 and ip-address-1/port-1. This allows the user to cut connections between a specified "client" and a particular service on a specified host. Our example closes host 10.10.0.45s SSH connection to server 200.1.2.3.

cutter ip-address-1 port-1 ip-address-2 port-2

Example: "cutter 200.1.2.3 22 10.10.0.45 32451"

Cuts the specific connection between the two ip/port number pairs given.

IMPORTANT WARNING

Cutter has been designed for use as a administrators tool for Linux firewalls. Its use (as is, or modified) for any other purpose is not sanctioned by the author. So - do not use this tool as a parachute, or to dry your cat, chill meat, answer your phone, drive you car, teach your kids to read or attack other peoples computer systems or networks.

This software has been designed for "legal" and "appropriate" use by network security administrators and the like. It has been written as part of a larger Linux firewall project, targetting at controlling traffic from peer-to-peer software such as Kazaa, iMesh and others into and out of a private network. It is not designed as a tool for malicious use and the author in no way sanctions such use.

Users of the software should be aware that its actions are easily detectable using a number of readily available network monitoring tools, and it makes no attempt to disguise its actions. Malicious use of "cutter" could result in a jail sentance in a number of countries around the world.