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Port 4480 (agtp, agtp-quic)

IANA assigns port 4480 to agtp, agtp-quic: Agent Transfer Protocol.

Registered (user) port, 1024-49151 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference
agtp TCP Agent Transfer Protocol Chris Hood -
agtp-quic UDP Agent Transfer Protocol over QUIC Chris Hood -

Registry dates for this port: registered 2026-04-30.

Check what is listening on port 4480

Linux: is anything listening on TCP 4480?
sudo ss -tlnp 'sport = :4480'
Linux: UDP 4480
sudo ss -ulnp 'sport = :4480'
Linux / macOS: which process owns the port
sudo lsof -nP -i :4480
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':4480 '
Windows (Command Prompt)
netstat -ano | findstr :4480
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 4480 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 4480
From Windows
Test-NetConnection HOST -Port 4480
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 4480

Block port 4480 in the firewall

ufw
sudo ufw deny 4480/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 4480 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 4480 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 4480' -Direction Inbound -Protocol TCP -LocalPort 4480 -Action Block
ufw
sudo ufw deny 4480/udp
iptables
sudo iptables -A INPUT -p udp --dport 4480 -j DROP
nftables
sudo nft add rule inet filter input udp dport 4480 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 4480' -Direction Inbound -Protocol UDP -LocalPort 4480 -Action Block

Related ports

4458mcp4460NTS-KE (Network Time Security)4484hpssmgmt4485assyst-dr

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