Lecture #21 - Asynchronous Transfer Mode (ATM)

ATM is a major traffic carrier used by telecommunication companies. ATM is also the core networking technology used to aggregate and connect ADSL tail circuits to ISPs. ATM provides for virtual circuits and can guarantee Quality of Service (QoS).
Some of the key concepts involved in ATM include:

• The basic unit of transmission is the cell. A cell is 53 bytes in length - 5 bytes of header and 48 bytes of payload. These small, fixed-format cells can be switched very quickly.
• ATM networks are based on connection-oriented cell relay - cells are multiplexed onto higher bitrate channels, but there is no timing relationship between individual cells within a particular connection. Cells may be dropped but are never delivered out of order.
• The telecommunications industry uses ATM as a basis for providing converged services, allowing for the seamless integration of voice (telephony), audio, video-on-demand, video conferencing, video broadcast and data, on the one network.
• ATM is complex. Even the telcos admit it has many unsolved problems.

ATM Background

• Designed in early 1990s, when both bandwidth and networking equipment was relatively expensive, and voice and data convergence was a hot topic in the industry.
• A technology evolved more from the telecommunications industry than the computer/data industry.
• Designed for high-performance mixed network traffic (voice, data, video, and future media applications).
• Designed for bursty traffic.
• Designed to replace all existing analog and digital communication backbone systems.
• A relatively expensive networking technology, mainly used among tier 1 and tier 2 telcos.
• Gigabit Ethernet (a much cheaper technology) has replaced ATM on many networks. ATM is Less popular now.
• Gigabit Ethernet is a natural upgrade path for Fast Ethernet.
• ATM offers QoS, but QoS issues can simply be overcome by providing a bigger pipe?

"Arguably, ATM is unnecessary if bandwidth is cheap and plentiful, and there is no congestion in the network."
"Experience has also shown that over-provisioning bandwidth does not resolve all QoS issues. Hence Gigabit Ethernet is not expected to replace ATM at this time."

ADSL Information

~ New! Broadband Availability Checker - Checks adsl line and exchange status.   ~ Max Speed Calculator - Indication of your maximum speed.   ~ How to get your line stats from your router   ~ How to understand your line stats   ~ Connecting and adsl filters.   ~ Networking and setting up a router   ~ How adsl works.   ~ Different types of adsl - IPStream, Datastream + LLU   ~ DSL Max & Interleaving   ~ How DSLMax works & your bRAS IP Profile information   ~ Troubleshooting and adsl connection problems   ~ Common Faults - Low SNR and REIN faults   ~ Understanding SNR and attenuation   ~ Slow speed problems   ~ MTU Problems and MTU tweaking                                                         

http://www.kitz.co.uk/adsl/index.htm

What is Clonezilla?

You're probably familiar with the popular proprietary commercial package Norton Ghost®. The problem with these kind of software packages is that it takes a lot of time to massively clone systems to many computers. You've probably also heard of Symantec's solution to this problem,Symantec Ghost Corporate Edition® with multicasting. Well, now there is an OpenSource clone system (OCS) solution called Clonezilla with unicasting and multicasting!
Clonezilla, based on DRBL, Partclone and udpcast, allows you to do bare metal backup and recovery. Two types of Clonezilla are available,Clonezilla live and Clonezilla SE (server edition). Clonezilla live is suitable for single machine backup and restore. While Clonezilla SE is for massive deployment, it can clone many (40 plus!) computers simultaneously. Clonezilla saves and restores only used blocks in the harddisk. This increases the clone efficiency. At the NCHC's Classroom C, Clonezilla SE was used to clone 41 computers simultaneously. It took only about 10 minutes to clone a 5.6 GBytes system image to all 41 computers via multicasting!

Perbedaan redirect to proxy memakai dst-nat dan mark-routing

Mungkin selama ini anda tidak pernah menyadari traffic sebuah server yang mengirimkan data atas permintaan ip klien jika menggunakan dst-nat to proxy itu server akan mengirim ke ip proxy bukan langsung ke ip klien yang telah melakukan permintaan tadi

Jadi kita akan mengalami kesulitan jika ingin membuat rule bypass/limit untuk ip server (port 80) yang dari luar yang telah masuk ke ip proxy

td 8117 exploit

http://carnal0wnage.attackresearch.com/
http://www.exploit-db.com/exploits/10276/
http://www.securityfocus.com/archive/1/349085
http://www.cvedetails.com

ultimate.sh

#!/bin/bash
# ultimate.sh for duron
# Based on Wonder Shaper v1.1a
echo "/usr/sbin/ultimate.sh:  "

# Please read the README before filling out these values.
# Set the following values to somewhat less than your actual download
# and upload speed in kilobits.  Also set the device that is to be shaped.

# Run a speed test from netspeed.stanford.edu with no shaping enabled.
# Multiply the reported rates in Kb/s by ~.95 and enter them here:
# Example: DNLINK=4.76M*.95 = 4522
#          UPLINK=444.26K*.95 = 422
# Run the stanford test again.  Note: stanford uses high ports.
# Tweak during heavy upload so that each affected class has a small backlog but
# as few dropped packets as possible.  Interactive must NEVER backlog!
# If heavy downloads affect uploads, tweak IMQ so there is a small backlog but
# as few dropped packets as possible.
# Watch the logs for "some class has too small rate" even with quantum set.
# Stanford is in class 30; egress rate 36% ceil 92%, ingress rate 57% ceil 92%
# Download w/HTB is plenty (5.2x), don't tweak.
# Upload w/UPLINK=470 -> range 416 - 420 = ~85% of uCEIL.  Try for 90% - 91%.

fw_function

#-----------------------
# FONCTIONS Firewall
# guibo@guibo.com
# version 1.2
# tested on slk
#-----------------------

load_module() {
IP_MODULES=`/sbin/lsmod | awk '{print $1}' | /bin/grep '^ip' | grep $1`
if [ -z "$IP_MODULES" ]; then
    if [ -e $PATH_modules/$1.$EXTENSION_module ]; then
            /sbin/insmod $PATH_modules/$1.$EXTENSION_module
            else
            echo " - MUST HAVE Compiled kernel $1 support"
    fi
fi
}

load_module_q() {
IP_MODULES=`/sbin/lsmod | awk '{print $1}'`
if [ -z "$IP_MODULES" ]; then
    if [ -e $PATH_modules_q/$1.$EXTENSION_module ]; then
            /sbin/insmod $PATH_modules_q/$1.$EXTENSION_module
            else
            echo " - MUST HAVE Compiled kernel $1 support"
    fi
fi
}