Protocols
A protocol is a set of rules and guidelines for communicating data. Rules are defined for each step and process during communication between two or more computers. Networks have to follow these rules to successfully transmit data.

IEEE 802.11 - Address Resolution Protocol (ARP) - Domain Name System (DNS) - Dynamic Host Configuration Protocol (DHCP) - File Transfer Protocol (FTP) - Hypertext Transfer Protocol (HTTP) - Hypertext Transfer Protocol Secure (HTTPS) - Internet Message Access Protocol (IMAP) - Internet Protocol version 4 (IP) - Internet Protocol version 6 (IPv6) - Lightweight Directory Access Protocol (LDAP) - Network File System (NFS) - Network Time Protocol (NTP) - Post Office Protocol (POP) - Post Office Protocol version 3 (POP3) - Rapid Spanning Tree Protocol (RSTP) - Real-time Transport Protocol (RTP) - Secure Shell (SSH) - Simple Mail Transfer Protocol (SMTP) - Simple Network Management Protocol (SNMP) - Spanning Tree Protocol (STP) - Syslog Protocol - Transmission Control Protocol (TCP) - User Datagram Protocol (UDP)

Address Resolution Protocol (ARP)

Domain Name System (DNS)

  • DNS is a hierarchical decentralized naming system for computers, services, or other resources connected to the Internet or a private network. UDP port 53, by default. If the data portion of the UDP packet exceeds the maximum size, then TCP port 53 is used.
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  • Applications and Tools
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  • References
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  • DDNS
    • DDNS
    • ChangeiP Free Dynamic DNS delivers the essentials DNS features including a free to use subdomain, unlimited URL redirections, and complete port redirection capabilities.
    • D-Link - dynamic DNS host name for your D-Link router
    • My DDNS is a free solution I developed.
    • no-ip allows remote access your computer, DVR, webcam, security camera or any internet connected device easily. Dynamic DNS points an easy to remember hostname to your dynamic IP address.
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  • DNS over HTTPS (DoH)

Dynamic Host Configuration Protocol (DHCP)

File Transfer Protocol (FTP)

  • FTP is a standard network protocol used for the transfer of computer files between a client and server on a computer network.
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  • Commands
    binarySets the file transfer type to binary. Critical to the successful transfer of files such as Word documents, graphics, or software packages; also works fine with text files (files that contain only ascii text and no formatting).
    get $filenameTransfers a file from a remote computer to the computer you are typing on.
    mget $file1 $file2Transfers multiple files from a remote computer to the computer you are typing on.
    lsLists all the files in your current sub-directory.
    cdChanges the directory. To move back up to a previous level, use \"cd ..\" (note the space).
    put $filenameTransfers a file from the computer you are typing on to the remote computer.
    mput $file1 $file2Transfers multiple files from the computer you are typing on to the remote computer.
    pwdTells you the present working directory.
    <Ctrl>+hDeletes a character to the left of the cursor (acts as a backspace). Note: Use the Ctrl key; don't type the word "Ctrl".
    help $commandDisplays the definition of a command. Type \"help\" to see a full list of valid commands.
    byeEnds the FTP session.
  • References

Hypertext Transfer Protocol (HTTP) / Hypertext Transfer Protocol Secure (HTTPS)

Internet Message Access Protocol (IMAP)

  • IMAP is an Internet standard protocol used by e-mail clients to retrieve e-mail messages from a mail server over a TCP/IP connection.
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  • References

Internet Protocol version 4 (IP) / Internet Protocol version 6 (IPv6)

  • IP is the principal communications protocol in the Internet protocol suite for relaying packets across network boundaries. Its routing function enables internetworking, and essentially establishes the Internet.
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  • Applications and Tools
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  • Special Use Subnets
    0.0.0.0/8self-identification
    10.0.0.0/8Private
    127.0.0.0/32Loopback
    169.254/16DHCP link local address
    172.16.0.0/12Private
    192.0.0.0/24Special Purpose
    192.0.2.0/24TEST-NET-1
    192.88.99.0/246to4 relay anycast
    192.88.99.2/326to4 relay anycast
    192.88.99.2/326to4 relay anycast
    192.168.0.0/16Private
    198.18.0.0/15Interconnect Device
    198.51.100.0/24TEST-NET-2
    203.0.113.0/24TEST-NET-3
    224.0.0.0/4Multicast
    240.0.0.0/4Reserved
    255.255.255.255/32Limited broadcast
    fc00::/7Unique Local Unicast
    fe80::/10Link Local Unicast
    ff00::/8Multicast
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  • IP Assignment
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  • References

Lightweight Directory Access Protocol (LDAP)

  • LDAP is an open, vendor-neutral, industry standard application protocol for accessing and maintaining distributed directory information services over an Internet Protocol (IP) network.
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  • Commands
    ldapbindUse ldapbind to authenticate to a directory server or find out if the server is running.
    ldapsearchUse ldapsearch to search for specific entries in a directory. ldapsearch opens a connection to a directory, authenticates the user performing the operation, searches for the specified entry, and prints the result in a format that the user specifies.
    ldapaddUse ldapadd to add entries to the directory. ldapadd opens a connection to the directory and authenticates the user. Then it opens the LDIF file supplied as an argument and adds, in succession, each entry in the file.
    ldapdeleteUse ldapdelete to remove leaf entries from a directory. ldapdelete opens a connection to a directory server and authenticates the user. Then it deletes specified entries.
    ldapmodifyUse ldapmodify to modify existing entries. ldapmodify opens a connection to the directory and authenticates the user. Then it opens the LDIF file supplied as an argument and modifies the LDAP entries specified by the file.
    ldapmoddnUse ldapmoddn to change the RDN of an entry or move an entry or subtree to another location in the directory
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  • References

Network File System (NFS)

  • NFS is a distributed file system protocol allows a user on a client computer to access files over a computer network much like local storage is accessed.
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  • References

Network Time Protocol (NTP)

Post Office Protocol version 3 (POP3)

  • POP is an application-layer Internet standard protocol used by e-mail clients to retrieve e-mail from a server in an Internet Protocol (IP) network.
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  • Commands
    USER Your user name for this mail server
    PASS Your password.
    QUITEnd your session.
    STATNumber and total size of all messages
    LIST Message# and size of message
    RETR $messageRetrieve selected message
    DELE $messageDelete selected message
    NOOPNo-op. Keeps you connection open.
    RSETReset the mailbox. Undelete deleted messages.
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  • Applications and Tools
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  • References

Real-time Transport Protocol (RTP)

Secure Shell (SSH)

  • SSH is a cryptographic network protocol for operating network services securely over an unsecured network.
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  • References

Simple Mail Transfer Protocol (SMTP)

  • SMTP is an Internet standard for electronic mail (email) transmission. Some ways to deal with Spam.
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  • Commands
    ATRNAuthenticated TURN
    AUTHAuthentication
    BDATBinary data
    BURLRemote content
    DATAThe actual email message to be sent
    This command is terminated with a line that contains only a
    EHLOExtended HELO
    ETRNExtended turn
    EXPNExpand
    HELOIdentify yourself to the SMTP server.
    HELPShow available commands
    MAILSend mail from email account
    MAIL FROM: me@mydomain.com
    NOOPNo-op. Keeps you connection open.
    ONEXOne message transaction only
    QUITEnd session
    RCPTSend email to recipient
    RCPT TO: you@yourdomain.com
    RSETReset
    SAMLSend and mail
    SENDSend
    SOMLSend or mail
    STARTTLS
    SUBMITTERSMTP responsible submitter
    TURNTurn
    VERBVerbose
    VRFYVerify
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  • Applications and Tools
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  • References

Simple Network Management Protocol (SNMP)

  • SNMP is used to communicate management information between the network management stations and the agents in the network elements.
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  • SNMP Security Levels
    Version Level Authentication Encryption What Happens
    v1 noAuthNoPriv Community String No Uses a community string match for authentication.
    v2c noAuthNoPriv Community String No Uses a community string match for authentication.
    v3 noAuthNoPriv Username No Uses a username match for authentication.
    v3 authNoPriv Message Digest Algorithm 5 (MD5) or Secure Hash Algorithm (SHA) No Provides authentication based on the Hashed Message Authentication Code (HMAC)-MD5 or HMAC-SHA algorithms.
    v3 authPriv Message Digest Algorithm 5 (MD5) or Secure Hash Algorithm (SHA) Data Encryption Standard (DES) Provides authentication based on the HMAC-MD5 or HMAC-SHA algorithms. In addition to authentication, provides DES 56-bit encryption based on the Cipher Block Chaining (CBC)-DES (DES-56) standard.
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  • Applications and Tools
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  • References

Spanning Tree Protocol (STP) / Rapid Spanning Tree Protocol (RSTP)

  • STP is a network protocol that builds a logical loop-free topology for Ethernet networks.
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  • References
    • IEEE 802.1D IEEE standard for local and metropolitan area networks--Media access control (MAC) Bridges (for STP and RSTP).
    • IEEE 802.1Q IEEE Standards for local and metropolitan area networks-—Virtual Bridged Local Area Networks (for MSTP).
    • Wireshark
    • wikipedia

Syslog Protocol

Transmission Control Protocol (TCP)

User Datagram Protocol (UDP)

  • UDP allows computer applications to send messages to other hosts on an Internet Protocol (IP) network. UDP has no handshaking. UDP packets are dropped on congested networks. Therefore, it is unclear if the message is delivered.
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  • References

 
 
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