Port 5900: VNC
Remote desktop over VNC, including VM consoles. Often has weak or no passwords. Hypervisor VNC consoles should only be reachable through the panel's proxy.
- Free
- No Sign-Up
- Runs in Your Browser
Port Lookup
Port 5900 at a glance
Port5900
ProtocolTCP
ServiceVNC
Open to the Internet?No, keep it on a private network
See What Is Listeningss -lntup | grep ':5900 '
Test From Outsidenc -zv your-server 5900
Block with UFWufw deny 5900/tcp
Block with nftablesnft add rule inet filter input tcp dport 5900 drop
VNC uses TCP port 5900. Remote desktop over VNC, including VM consoles.
Often has weak or no passwords. Hypervisor VNC consoles should only be reachable through the panel's proxy.
If ss shows something listening on port 5900 on a public address, bind it to 127.0.0.1 or a private interface in the service's own configuration, and drop the port in the firewall as well.
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 5900 used for?
VNC. Remote desktop over VNC, including VM consoles.
Is it safe to open port 5900?
No, keep it on a private network. Often has weak or no passwords. Hypervisor VNC consoles should only be reachable through the panel's proxy.
How do I check if port 5900 is open?
On the server, ss -lntup | grep ':5900 ' shows what is listening. From another machine, nc -zv your-server 5900 shows whether the firewall lets it through.
How do I block port 5900?
With UFW: ufw deny 5900/tcp. With nftables, add a drop rule for dport 5900 in your input chain.
Free Tools
More tools
Port LookupWhat runs on a TCP or UDP port, and whether it should be open.Firewall Rule GeneratorGenerate iptables, nftables and UFW rules for common server set-ups.What Is My IPYour public IP address, reverse DNS, network and ASN.IP Reputation CheckerCheck an IP against spam blocklists and threat feeds at once.
Abuse from open ports on your VMs?
Frabs spots amplification, scans and floods leaving any VM and stops them, without touching your firewall.