Port 53 is extremely sub-optimal for OpenVPN. Some providers block access to external DNS (UDP port 53). I’m sitting on a hotel network now where that is the case.

No HTTP port 53 mentioned, all goes via port 80. Pretty clear that you might see also DNS traffic over port 53 (UDP, maybe TCP) to at the same time, or better milliseconds before, because this domain choices.truste.com needs to be resolved, of course. Oct 31, 2009 · DNS uses UDP for DNS Queries over Port: 53. A client computer will always send a DNS Query using UDP Protocol over Port 53. If a client computer does not get response from a DNS Server, it must re-transmit the DNS Query using the TCP after 3-5 seconds of interval. TCP port 21 — FTP (File Transfer Protocol) TCP port 22 — SSH (Secure Shell) TCP port 23 — Telnet. TCP port 25 — SMTP (Simple Mail Transfer Protocol) TCP and UDP port 53 — DNS (Domain Name System) Port 88 (UDP) Port 3074 (UDP and TCP) Port 53 (UDP and TCP) Port 80 (TCP) Port 500 (UDP) Port 3544 (UDP) Port 4500 (UDP) The problem: 53 is DNS server! 80 is web/HTML, 88 is Kerberos Auth, 500 IKE key exchange port! All of these ports are for real world things not an xbox. Apr 21, 2010 · It's UDP Port 53 you need to look for, you would expect to see: UDP IPAddress:53 *:* UDP *:* Or an entry for each address. TCP is used for Zone Transfers and little else, you don't need your DNS Server to listen for that. UDP is used for standard queries.

Jan 12, 2012 · For example, the low overhead of UDP with his short header enables DNS to serve many client requests very quickly. However, sending the requested information sometimes may require the reliability of TCP. In that case, the port number of 53 that is a well known port number is used by both protocols with this service.

UDP Port 53 may use a defined protocol to communicate depending on the application. A protocol is a set of formalized rules that explains how data is communicated over a network. Think of it as the language spoken between computers to help them communicate more efficiently.

2. Port 53: Port 53 is used by DNS. Let’s see one DNS packet capture. Here is trying to send DNS query. So destination port should be port 53. Now we put “udp.port == 53” as Wireshark filter and see only packets where port is 53. 3. Port 443: Port 443 is used by HTTPS. Let’s see one HTTPS packet capture.

Guaranteed communication over port 53 is the key difference between TCP and UDP. UDP port 53 would not have guaranteed communication in the same way as TCP. Because protocol TCP port 53 was flagged as a virus (colored red) does not mean that a virus is using port 53, but that a Trojan or Virus has used this port in the past to communicate. Jun 30, 2020 · ALLOW TCP/UDP IN/OUT to or on Port 53. and. BLOCK TCP/UDP IN/OUT all IP addresses on Port 53 The first rule trumps the second rule. Put simply, any requests to OpenDNS will be allowed and any requests to any other IP will be blocked. Oct 10, 2018 · This check udp port article will talk about the User Datagram Protocol, what is used for and the tool to use it. User Datagram Protocol (UDP) is like a send and forget protocol. To check if the UDP port is open or not, you should receive a response from the port. Mar 26, 2013 · I am using PortQry to check the port connectivity between my Domain Controllers located in different sites. All the Domain Controllers return DNS Query to UDP Port 53 whereas only one site's Domain Controllers including the PDC returns the query as timed out. I have checked after disabling the windows firewall as well. b) As soon as we type in google.com we get an output showing the server and an IP-address#port. This server is basically the current DNS server that will be serving our request. In this case it is and the port no is 53. This is because DNS uses UDP port 53 to serve its requests.