Port 464 (Kerberos password change)

kpasswd: changing Kerberos passwords (used by Active Directory domain controllers).

Well-known (system) port, 0-1023 TCPUDP Directory and authentication Do not expose to the internet

What port 464 is used for

kpasswd: changing Kerberos passwords (used by Active Directory domain controllers).

Do not expose to the internet. Internal only, alongside port 88.

Service nameProtoDescriptionAssigneeReference

kpasswd TCP kpasswd Greg Hudson 2 -

kpasswd UDP kpasswd Greg Hudson 2 -

Registry dates for this port: last modified 2023-11-17.

Linux: is anything listening on TCP 464?

sudo ss -tlnp 'sport = :464'

Linux: UDP 464

sudo ss -ulnp 'sport = :464'

Linux / macOS: which process owns the port

sudo lsof -nP -i :464

Older Linux / BSD (net-tools)

sudo netstat -tlnp | grep ':464 '

Windows (Command Prompt)

netstat -ano | findstr :464

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 464 -State Listen | Select LocalAddress,OwningProcess

From another machine

nc -vz -w 5 HOST 464

From Windows

Test-NetConnection HOST -Port 464

UDP probe (no reply does not prove it is closed)

nc -vzu -w 5 HOST 464

ufw

sudo ufw deny 464/tcp

iptables

sudo iptables -A INPUT -p tcp --dport 464 -j DROP

nftables

sudo nft add rule inet filter input tcp dport 464 drop

Windows Firewall

New-NetFirewallRule -DisplayName 'Block TCP 464' -Direction Inbound -Protocol TCP -LocalPort 464 -Action Block

ufw

sudo ufw deny 464/udp

iptables

sudo iptables -A INPUT -p udp --dport 464 -j DROP

nftables

sudo nft add rule inet filter input udp dport 464 drop

Windows Firewall

New-NetFirewallRule -DisplayName 'Block UDP 464' -Direction Inbound -Protocol UDP -LocalPort 464 -Action Block

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Assignment data: IANA port number registry (public domain), retrieved 2026-11-10.