The File Transfer Protocol (FTP)

The File Transfer Protocol (FTP) is a widely utilized method for exchanging files over IP networks. Beyond the primary control connection, additional data connections facilitate file transfers between the client and the server, with the host, port, and direction negotiated via the control channel.

In active mode FTP, the firewall service scans client-to-server application data for the PORT command, which specifies the IP address and port number to which the server connects.

Conversely, in passive mode FTP, the firewall service scans client-to-server data for the PASV command and then examines server-to-client responses for the 227 response, containing the IP address and port number to which the client connects. FTP represents addresses and port numbers in ASCII.

Consequently, when addresses and ports are rewritten, the TCP sequence number might change, necessitating the NAT service to maintain this delta in SEQ and ACK numbers by performing sequence NAT on all subsequent packets.

The FTP ALG (Application Layer Gateway) offers the following capabilities:

• Automatic allocation of data ports and firewall permissions for dynamic data connections.
• Monitoring of the control connection in both active and passive modes.
• Rewriting of control packets with the appropriate NAT address and port information.

Additionally, FTP ALG supports Network Address Translation, Protocol Translation (NAT-PT), and uses Transport Layer Security (TLS) as a security mechanism.

Are you looking for help to upgrade your current network? Contact the Solution Architects at Cloudtitude , we make the intricate—simple.

?? Call: (346) 800-1148

??? Book a meeting: https://lnkd.in/gBWMKDfd

?? Contact: https://lnkd.in/gkXWVmcS

#VoIP #BusinessCommunication #ITSupport #ElevateYourBusiness #FutureOfVoIP #BusinessCommunication #PhoneUpgrade #Cloudtitude #voip #phonesystem #conferenceroom #telecommunications #unifiedcommunications #yealink #cisco #m365 #telecom #MSP #Azure #Cloud #ManagedServices #TechSupport #ITSupport #Microsoft365 #CyberSec #EDR #Backups #Patching #RemoteSupport #Houston #Texas