← Port Encyclopedia
691
MS-Exchange
TCP
Email
Medium Risk
MS Exchange routing — Microsoft Exchange server communication
🔍 How to Scan Port 691
nmap -sV -p 691 target
nmap -sV -sC --script=banner -p 691 target
nc -zv target 691
🛡️ Security Considerations
- Scan port 691 with
nmap -sVto identify the exact service and version - If MS-Exchange is not needed, close or firewall this port immediately
- Check for default credentials if a management interface runs on this port
- Use
searchsploit ms-exchangeto find known exploits - Monitor traffic on port 691 with Wireshark or tcpdump for anomalies
- Ensure the service is patched to the latest version to prevent known CVE exploitation