All ports
Port77/UDP
Port
77
Protocol
UDP
Category
Well-Known
Service
Unassigned
What is port 77?
Port 77/UDP is a Well-Known port, assigned by IANA for widely recognized services. It currently has no assigned service in the IANA registry.
any private RJE service
Useful commands
nmapnmap -p 77 -sV example.comnetcatnc -zv example.com 77curlcurl -v http://example.com:77/telnettelnet example.com 77bash(echo > /dev/udp/example.com/77) 2>/dev/nullFirewall commands
UFWAllow
sudo ufw allow 77/udpDeny
sudo ufw deny 77/udpiptablesAllow
sudo iptables -A INPUT -p udp --dport 77 -j ACCEPTDeny
sudo iptables -D INPUT -p udp --dport 77 -j ACCEPTfirewalldAllow
sudo firewall-cmd --permanent --add-port=77/udpWindowsAllow
netsh advfirewall firewall add rule name="Open Port 77" dir=in action=allow protocol=UDP localport=77Security Risks
- Unauthorized access to the service
- Data exposure if the service is unauthenticated
- Outdated versions with vulnerabilities
- Incorrect service configuration
Frequently Asked Questions
What service runs on port 77/UDP?
Port 77/UDP is associated with the Unassigned service. any private RJE service
Is it safe to expose port 77 to the Internet?
It depends on the service and configuration. Port 77 (Unassigned) is a Well-Known port. If you need to expose it, keep the service updated, use strong authentication, and configure a firewall. It's always recommended to restrict access by IP when possible.
How do I check if port 77 is open?
You can use nmap: `nmap -p 77 -sV example.com`, netcat: `nc -zv example.com 77`, or the bash command: `(echo > /dev/udp/example.com/77) 2>/dev/null && echo "Open" || echo "Closed"`.
How do I open or close port 77 on my firewall?
On Linux with UFW: `sudo ufw allow 77/udp` (open) or `sudo ufw deny 77/udp` (close). With iptables: `sudo iptables -A INPUT -p udp --dport 77 -j ACCEPT`. On Windows: `netsh advfirewall firewall add rule name="Open Port 77" dir=in action=allow protocol=UDP localport=77`.
What applications and services use port 77?
Port 77/UDP is used by the Unassigned service. Specific uses depend on the software and configuration. Check our related tools section for more information.