System Configuration Guide for Cisco Unified

FTP uses TCP ports 21 and 20. You can learn “everything” about FTP here → RFC 959 - File Transfer Protocol. I recommend reading one of these: * FTP for Beginners * Understanding How FTP Works Warning: 1. Files transferred are not encrypted and mor Extending TFTP - CompuPhase So, your browser made a "hole" in the NAT router/firewall, so to speak, but only for that single connection. UDP hole punching is an extension of this for the case that the client (e.g. your browser) and the server are both behind a NAT router/firewall. TFTP uses UDP as the transport protocol, rather than TCP. network protocols, TFTP, SMTP, TCP, UDP, ARP, RARP, TCP/IP Mar 25, 2018

I need to retrieve both TCP and UDP ports in the same scan with Nmap in the fastest way possible. I'll try to explain it better. If I use the most common command: nmap It retrieves ONLY TCP ports and it is really fast. If I use the following command: nmap -sU

But it may be that there is a TFTP implementation that uses TCP, and if so, I'm afraid I have no exposure to it. Domain Name System (DNS) is traditionally the protocol referred to when discussing protocols that use both TCP and UDP. It doesn't use these at the same time, mind you. But different functions within DNS might call for TCP vs UDP. TCP vs. UDP: Understanding the Difference

Re: TFTP server and port 69 UDP or TCP or Both zillah2004, I think your example is different, as DNS works on UDP for client queries and TCP for zone transfert between servers. So it uses the same port, but has got different function on different layer 4 protocol.

Transmission control protocol (TCP) User datagram protocol (UDP) UDP is used by DNS, DHCP, TFTP, SNMP, RIP, and VoIP. A short example to understand the differences clearly : Suppose there are two houses, H1 and H2 and a letter have to be sent from H1 to H2. But there is … Difference Between TCP and UDP (with Comparison Chart Apr 13, 2016 UDP و TCP الفرق بين بروتوكول – IT Solutions كل من tcp و udp هما بروتوكولات تستخدم لإرسال أجزاء من البيانات تعرف باسم الحزم عبر الإنترنت. و كلاهما بناء على أعلى بروتوكول متاح في الإنترنت. بمعنى آخر ، سواء كنت ترسل حزمة عبر tcp أو udp ، يتم إرسال هذه الحزمة إلى عنوان ip معين . Does FTP use UDP? - Quora