Port 6253 (crip)

IANA assigns port 6253 to crip: CRIP.

Registered (user) port, 1024-49151 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference

crip TCP CRIP Mike Rodbell -

crip UDP CRIP Mike Rodbell -

Linux: is anything listening on TCP 6253?

sudo ss -tlnp 'sport = :6253'

Linux: UDP 6253

sudo ss -ulnp 'sport = :6253'

Linux / macOS: which process owns the port

sudo lsof -nP -i :6253

Older Linux / BSD (net-tools)

sudo netstat -tlnp | grep ':6253 '

Windows (Command Prompt)

netstat -ano | findstr :6253

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 6253 -State Listen | Select LocalAddress,OwningProcess

From another machine

nc -vz -w 5 HOST 6253

From Windows

Test-NetConnection HOST -Port 6253

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

nc -vzu -w 5 HOST 6253

ufw

sudo ufw deny 6253/tcp

iptables

sudo iptables -A INPUT -p tcp --dport 6253 -j DROP

nftables

sudo nft add rule inet filter input tcp dport 6253 drop

Windows Firewall

New-NetFirewallRule -DisplayName 'Block TCP 6253' -Direction Inbound -Protocol TCP -LocalPort 6253 -Action Block

ufw

sudo ufw deny 6253/udp

iptables

sudo iptables -A INPUT -p udp --dport 6253 -j DROP

nftables

sudo nft add rule inet filter input udp dport 6253 drop

Windows Firewall

New-NetFirewallRule -DisplayName 'Block UDP 6253' -Direction Inbound -Protocol UDP -LocalPort 6253 -Action Block

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