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Port 3256 (cpqrpm-agent)

IANA assigns port 3256 to cpqrpm-agent: Compaq RPM Agent Port.

Registered (user) port, 1024-49151 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference
cpqrpm-agent TCP Compaq RPM Agent Port - -
cpqrpm-agent UDP Compaq RPM Agent Port - -

Check what is listening on port 3256

Linux: is anything listening on TCP 3256?
sudo ss -tlnp 'sport = :3256'
Linux: UDP 3256
sudo ss -ulnp 'sport = :3256'
Linux / macOS: which process owns the port
sudo lsof -nP -i :3256
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':3256 '
Windows (Command Prompt)
netstat -ano | findstr :3256
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 3256 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 3256
From Windows
Test-NetConnection HOST -Port 3256
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 3256

Block port 3256 in the firewall

ufw
sudo ufw deny 3256/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 3256 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 3256 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 3256' -Direction Inbound -Protocol TCP -LocalPort 3256 -Action Block
ufw
sudo ufw deny 3256/udp
iptables
sudo iptables -A INPUT -p udp --dport 3256 -j DROP
nftables
sudo nft add rule inet filter input udp dport 3256 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 3256' -Direction Inbound -Protocol UDP -LocalPort 3256 -Action Block

Related ports

3254pda-sys3255semaphore3257cpqrpm-server3258ivecon-port

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