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Port 595 (cab-protocol)

IANA assigns port 595 to cab-protocol: CAB Protocol.

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

IANA assignment

Service nameProtoDescriptionAssigneeReference
cab-protocol TCP CAB Protocol Winston Hetherington -
cab-protocol UDP CAB Protocol Winston Hetherington -

Check what is listening on port 595

Linux: is anything listening on TCP 595?
sudo ss -tlnp 'sport = :595'
Linux: UDP 595
sudo ss -ulnp 'sport = :595'
Linux / macOS: which process owns the port
sudo lsof -nP -i :595
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':595 '
Windows (Command Prompt)
netstat -ano | findstr :595
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 595 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 595
From Windows
Test-NetConnection HOST -Port 595
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 595

Block port 595 in the firewall

ufw
sudo ufw deny 595/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 595 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 595 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 595' -Direction Inbound -Protocol TCP -LocalPort 595 -Action Block
ufw
sudo ufw deny 595/udp
iptables
sudo iptables -A INPUT -p udp --dport 595 -j DROP
nftables
sudo nft add rule inet filter input udp dport 595 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 595' -Direction Inbound -Protocol UDP -LocalPort 595 -Action Block

Related ports

593RPC over HTTP594tpip596smsd597ptcnameservice

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