Port 51820: WireGuard
WireGuard VPN's default port. Safe to expose: WireGuard stays silent to anyone without a valid key.
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Port Lookup
Port 51820 at a glance
Port51820
ProtocolUDP
ServiceWireGuard
Open to the Internet?Yes, if you run this service publicly
See What Is Listeningss -lntup | grep ':51820 '
Test From Outsidenmap -sU -p 51820 your-server
Block with UFWufw deny 51820/udp
Block with nftablesnft add rule inet filter input udp dport 51820 drop
WireGuard uses UDP port 51820. WireGuard VPN's default port.
Safe to expose: WireGuard stays silent to anyone without a valid key.
Open port 51820 only on servers that run WireGuard, and keep the software patched: public services are scanned within minutes of going online.
Other Ports
20 FTP Data21 FTP22 SSH23 Telnet25 SMTP53 DNS67 DHCP Server80 HTTP110 POP3123 NTP143 IMAP161 SNMP389 LDAP443 HTTPS445 SMB465 SMTPS514 Syslog587 Mail Submission853 DNS over TLS993 IMAPS995 POP3S1194 OpenVPN1433 Microsoft SQL Server1900 SSDP / UPnP2049 NFS2083 cPanel (SSL)2087 WHM (SSL)3306 MySQL / MariaDB3389 RDP3478 STUN / TURN5060 SIP5432 PostgreSQL5900 VNC6379 Redis8006 Proxmox VE8080 HTTP Alternate8443 HTTPS Alternate11211 Memcached25565 Minecraft27017 MongoDB51820 WireGuard
Questions
What is port 51820 used for?
WireGuard. WireGuard VPN's default port.
Is it safe to open port 51820?
Yes, if you run this service publicly. Safe to expose: WireGuard stays silent to anyone without a valid key.
How do I check if port 51820 is open?
On the server, ss -lntup | grep ':51820 ' shows what is listening. From another machine, nmap -sU -p 51820 your-server shows whether the firewall lets it through.
How do I block port 51820?
With UFW: ufw deny 51820/udp. With nftables, add a drop rule for dport 51820 in your input chain.
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