Common File Transfer Protocols

File Transfer Protocols

• TFTP (Trivial File Transfer Protocol) uses UDP port 69 and is not secure, as it doesn't encrypt traffic and has no authentication.
• Advantages of TFTP include low overhead, making it suitable for lab environments and firmware updates.
• However, TFTP is not recommended for general use due to its lack of security.

FTP

• FTP (File Transfer Protocol) uses TCP port 21 for the control channel and port 20 for the data channel (or dynamically negotiates it).
• FTP is not secure, as it doesn't encrypt data and has limited authentication, making it vulnerable to eavesdropping and man-in-the-middle attacks.

Restricting Insecure Protocols

• To prevent the use of insecure protocols like TFTP and FTP, filters can be applied to block UDP port 69 and TCP ports 21 and 20.
• This can be done at the network layer to restrict users from using these protocols.

Secure FTP

• SFTP (Secure File Transfer Protocol) uses TCP port 22 and leverages SSH technology to provide secure file transfers.
• SFTP is a recommended alternative to insecure protocols like TFTP and FTP.

SMB

• SMB (Server Message Block) is a file service used in Windows Active Directory and Microsoft Networking.

• SMB uses TCP port 445, as well as TCP port 139 and UDP port 445.

  SMB (Server Message Block) protocol can use both TCP and UDP for different purposes. TCP port 445 is the standard port used for SMB over IP networks. TCP port 139 was the traditional port used for SMB before port 445 became the standard. Some systems may still use port 139 for compatibility reasons.

  UDP port 445 is used for SMB directly over NetBIOS, which is an older networking protocol. NetBIOS over TCP (NBT) uses UDP port 137 and 138 for name resolution and datagram services. In some cases, UDP is used for better performance in certain SMB operations like browsing and name resolution, as it is connectionless and can be faster for certain types of data transmissions.

  In summary, SMB utilizes TCP port 445 as the primary port for file and print sharing over IP networks. TCP port 139 may still be used for compatibility reasons. UDP port 445 is used for SMB over NetBIOS, with ports 137 and 138 handling specific services related to NetBIOS communication.Analyzing log files and packet captures can help confirm the ports used by SMB and other protocols.

Memorization of Ports

• It's recommended to memorize the well-known ports for TFTP (UDP 69), FTP (TCP 21), SFTP (TCP 22), and SMB (TCP 445 and 139, UDP 445).
• This knowledge can be useful when working with logs or troubleshooting issues with these protocols.

Learn about different file transfer protocols used to move files between devices over a network, including TFTP and other common methods.