Port 443: HTTPS
Encrypted web traffic. UDP 443 carries HTTP/3 (QUIC). The one port almost every public server opens.
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Port Lookup
Port 443 at a glance
Port443
ProtocolTCP/UDP
ServiceHTTPS
Open to the Internet?Yes, if you run this service publicly
See What Is Listeningss -lntup | grep ':443 '
Test From Outsidenc -zv your-server 443
Block with UFWufw deny 443/tcp; ufw deny 443/udp
Block with nftablesnft add rule inet filter input meta l4proto { tcp, udp } th dport 443 drop
HTTPS uses TCP/UDP port 443. Encrypted web traffic. UDP 443 carries HTTP/3 (QUIC).
The one port almost every public server opens.
Open port 443 only on servers that run HTTPS, 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 443 used for?
HTTPS. Encrypted web traffic. UDP 443 carries HTTP/3 (QUIC).
Is it safe to open port 443?
Yes, if you run this service publicly. The one port almost every public server opens.
How do I check if port 443 is open?
On the server, ss -lntup | grep ':443 ' shows what is listening. From another machine, nc -zv your-server 443 shows whether the firewall lets it through.
How do I block port 443?
With UFW: ufw deny 443/tcp and ufw deny 443/udp. With nftables, add a drop rule for dport 443 in your input chain.
Free Tools
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