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Port 425 (icad-el)

IANA assigns port 425 to icad-el: ICAD.

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

IANA assignment

Service nameProtoDescriptionAssigneeReference
icad-el TCP ICAD Larry Stone -
icad-el UDP ICAD Larry Stone -

Check what is listening on port 425

Linux: is anything listening on TCP 425?
sudo ss -tlnp 'sport = :425'
Linux: UDP 425
sudo ss -ulnp 'sport = :425'
Linux / macOS: which process owns the port
sudo lsof -nP -i :425
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':425 '
Windows (Command Prompt)
netstat -ano | findstr :425
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 425 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 425
From Windows
Test-NetConnection HOST -Port 425
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 425

Block port 425 in the firewall

ufw
sudo ufw deny 425/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 425 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 425 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 425' -Direction Inbound -Protocol TCP -LocalPort 425 -Action Block
ufw
sudo ufw deny 425/udp
iptables
sudo iptables -A INPUT -p udp --dport 425 -j DROP
nftables
sudo nft add rule inet filter input udp dport 425 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 425' -Direction Inbound -Protocol UDP -LocalPort 425 -Action Block

Related ports

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