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Port 318 (pkix-timestamp)

IANA assigns port 318 to pkix-timestamp: PKIX TimeStamp.

Well-known (system) port, 0-1023 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference
pkix-timestamp TCP PKIX TimeStamp Robert Zuccherato -
pkix-timestamp UDP PKIX TimeStamp Robert Zuccherato -

Check what is listening on port 318

Linux: is anything listening on TCP 318?
sudo ss -tlnp 'sport = :318'
Linux: UDP 318
sudo ss -ulnp 'sport = :318'
Linux / macOS: which process owns the port
sudo lsof -nP -i :318
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':318 '
Windows (Command Prompt)
netstat -ano | findstr :318
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 318 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 318
From Windows
Test-NetConnection HOST -Port 318
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 318

Block port 318 in the firewall

ufw
sudo ufw deny 318/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 318 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 318 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 318' -Direction Inbound -Protocol TCP -LocalPort 318 -Action Block
ufw
sudo ufw deny 318/udp
iptables
sudo iptables -A INPUT -p udp --dport 318 -j DROP
nftables
sudo nft add rule inet filter input udp dport 318 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 318' -Direction Inbound -Protocol UDP -LocalPort 318 -Action Block

Related ports

316decauth317zannet319ptp-event320ptp-general

All port numbers · Open port checker
Assignment data: IANA port number registry (public domain), retrieved 2026-11-10.