Free connections etc software for linux

conn-close gives us possibility to get rid of entries in ip_conntrack about ESTABLISHED TCP connections that goes through our server.

conn-close script uses hping2 to send spoofed RST packets which will fool conntrack and cause specified connections to be considered by conntrack as closed (now these connections will be in ip_conntrack in CLOSE state), even though RST packets will be more likely discarded by destination host.

Information about connections is read of course from /proc/net/ip_conntrack.

Idea was taken from script seen somewhere on the internet.

QoS Connection Tuning HOWTO is a document which explains how to tune network connection performance.

This enables you to get the maximum benefit out of your connection without lag and loss.

Gnome Remote Connection Manager is a gnome application that stores information
about remote connections.
It gives you a GUI program to launch applications like telnet, shh, or rdesktop. It is highly configurable as to what type of applications it launches, so you are not limited to the three listed, for example I never thought of using it for ftp, but it would be easy to setup.
GRCM uses gconf to store information about connections.
Enhancements:
- Added some missing icons.
- Fixed a callback in the Connections Dialog that made the default arguments from the connection appear when selected.

Gtk2::Ex::MindMapView::Connection is a Perl module to draw connections between view items.

HEIRARCHY

Glib::Object
+----Gtk2::Object
+----Gnome2::Canvas::Item
+----Gnome2::Canvas::Shape
+----Gnome2::Canvas::Bpath
+----Gtk2::Ex::MindMapView::Connection

SYNOPSIS

use Gtk2::Ex::MindMapView::Connection;

This module is internal to Gtk2::Ex::MindMapView. Connections are instantiated by Gtk2::Ex::MindMapView. This module is responsible for drawing the connecting lines between Gtk2::Ex::MindMapView::Items onto the canvas.

The Gtk2::Ex::MindMapView::Connection is an observer. It registers with the view items so that it may be notified when a view items state changes.

INTERFACE

Properties

arrows (string : readable / writable)

Indicates whether arrows should be drawn. Possible values are: none, one-way, and two-way.

predecessor_item (Gtk2::Ex::MindMapView::Item : readable / writable)

The item at which this connection starts.

item (Gtk2::Ex::MindMapView::Item : readable / writable)

The item at which this connection ends.

Methods

INIT_INSTANCE

This subroutine is called by Glib::Object::Subclass as the object is being instantiated. You should not call this subroutine directly. Leave it alone.

SET_PROPERTY

This subroutine is called by Glib::Object::Subclass when a property is being set. You should not call this subroutine directly. Leave it alone. Instead call the set method to assign values to properties.

connect

Connect the Gtk2::Ex::MindMapView::Connection to the items it observes.

disconnect

Disconnect the Gtk2::Ex::MindMapView::Connection from the items it observes.

NetworkManager Applet project is used as a network connection manager for most RPM and Debian-based distros.

Supports Ethernet, WiFi, VPN connections.

Encode::PerlIO is a detailed document on Encode and PerlIO.

Overview

It is very common to want to do encoding transformations when reading or writing files, network connections, pipes etc. If Perl is configured to use the new perlio IO system then Encode provides a "layer" (see PerlIO) which can transform data as it is read or written.

Here is how the blind poet would modernise the encoding:

use Encode;
open(my $iliad,:utf8,iliad.utf8);
my @epic = < $iliad >;
print $utf8 @epic;
close($utf8);
close($illiad);

In addition, the new IO system can also be configured to read/write UTF-8 encoded characters (as noted above, this is efficient):

open(my $fh,>:utf8,anything);
print $fh "Any x{0021} string N{SMILEY FACE}n";

Either of the above forms of "layer" specifications can be made the default for a lexical scope with the use open ... pragma. See open.

Once a handle is open, its layers can be altered using binmode.

Without any such configuration, or if Perl itself is built using the systems own IO, then write operations assume that the file handle accepts only bytes and will die if a character larger than 255 is written to the handle. When reading, each octet from the handle becomes a byte-in-a-character. Note that this default is the same behaviour as bytes-only languages (including Perl before v5.6) would have, and is sufficient to handle native 8-bit encodings e.g. iso-8859-1, EBCDIC etc. and any legacy mechanisms for handling other encodings and binary data.
In other cases, it is the programs responsibility to transform characters into bytes using the API above before doing writes, and to transform the bytes read from a handle into characters before doing "character operations" (e.g. lc, /W+/, ...).

You can also use PerlIO to convert larger amounts of data you dont want to bring into memory. For example, to convert between ISO-8859-1 (Latin 1) and UTF-8 (or UTF-EBCDIC in EBCDIC machines):

open(F, ":utf8", "data.utf") or die $!;
while (< F >) { print G }

# Could also do "print G < F >" but that would pull
# the whole file into memory just to write it out again.

More examples:

open(my $f, ":encoding(iso-8859-2)")
open(my $h, ">:encoding(latin9)") # iso-8859-15

tsocks provides transparent network access through a SOCKS version 4 or 5 proxy (usually on a firewall).

SOCKS servers are a form of proxy that are commonly used in firewalled LAN environments to allow access between networks, and often to the Internet. The problem is that most applications dont know how to gain access through SOCKS servers. This means that network based applications that dont understand SOCKS are very limited in networks they can reach. An example of this is simple telnet.

tsocks role is to allow these non SOCKS aware applications (e.g telnet, ssh, ftp etc) to use SOCKS without any modification. It does this by intercepting the calls that applications make to establish network connections and negotating them through a SOCKS server as necessary. If youre on a network firewalled from the internet with a SOCKS server for outside access, telnet cant use this server and thus cant telnet out to the Internet., sou you cannot get out.

tsocks is based on the shared library interceptor concept. Through use of the LD_PRELOAD environment variable or the /etc/ld.so.preload file tsocks is automatically loaded into the process space of every executed program. From there it overrides the normal connect() function by providing its own. Thus when an application calls connect() to establish a TCP connection it instead passes control to tsocks. tsocks determines if the connection needs to be made via a SOCKS server (by checking /etc/tsocks.conf) and negotiates the connection if so (through use of the real connect() function )