All ports

Port17/TCP

qotd

Port

17

Protocol

TCP

Category

Well-Known

Service

qotd

What is port 17?

Port 17/TCP is a Well-Known port, assigned by IANA for widely recognized services. It is associated with the qotd service.

Quote of the Day

Useful commands

nmapnmap -p 17 -sV example.com
netcatnc -zv example.com 17
curlcurl -v http://example.com:17/
telnettelnet example.com 17
bash(echo > /dev/tcp/example.com/17) 2>/dev/null

Firewall commands

UFWAllow
sudo ufw allow 17/tcp
Deny
sudo ufw deny 17/tcp
iptablesAllow
sudo iptables -A INPUT -p tcp --dport 17 -j ACCEPT
Deny
sudo iptables -D INPUT -p tcp --dport 17 -j ACCEPT
firewalldAllow
sudo firewall-cmd --permanent --add-port=17/tcp
WindowsAllow
netsh advfirewall firewall add rule name="Open Port 17" dir=in action=allow protocol=TCP localport=17

Security 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  • Outdated versions with vulnerabilities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 17/TCP?

Port 17/TCP is associated with the qotd service. Quote of the Day

Is it safe to expose port 17 to the Internet?

It depends on the service and configuration. Port 17 (qotd) 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 17 is open?

You can use nmap: `nmap -p 17 -sV example.com`, netcat: `nc -zv example.com 17`, or the bash command: `(echo > /dev/tcp/example.com/17) 2>/dev/null && echo "Open" || echo "Closed"`.

How do I open or close port 17 on my firewall?

On Linux with UFW: `sudo ufw allow 17/tcp` (open) or `sudo ufw deny 17/tcp` (close). With iptables: `sudo iptables -A INPUT -p tcp --dport 17 -j ACCEPT`. On Windows: `netsh advfirewall firewall add rule name="Open Port 17" dir=in action=allow protocol=TCP localport=17`.

What applications and services use port 17?

Port 17/TCP is used by the qotd service. Specific uses depend on the software and configuration. Check our related tools section for more information.