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Port 1520 (atm-zip-office)

IANA assigns port 1520 to atm-zip-office: atm zip office.

Registered (user) port, 1024-49151 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference
atm-zip-office TCP atm zip office Wilson Kwan -
atm-zip-office UDP atm zip office Wilson Kwan -

Check what is listening on port 1520

Linux: is anything listening on TCP 1520?
sudo ss -tlnp 'sport = :1520'
Linux: UDP 1520
sudo ss -ulnp 'sport = :1520'
Linux / macOS: which process owns the port
sudo lsof -nP -i :1520
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':1520 '
Windows (Command Prompt)
netstat -ano | findstr :1520
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 1520 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 1520
From Windows
Test-NetConnection HOST -Port 1520
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 1520

Block port 1520 in the firewall

ufw
sudo ufw deny 1520/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 1520 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 1520 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 1520' -Direction Inbound -Protocol TCP -LocalPort 1520 -Action Block
ufw
sudo ufw deny 1520/udp
iptables
sudo iptables -A INPUT -p udp --dport 1520 -j DROP
nftables
sudo nft add rule inet filter input udp dport 1520 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 1520' -Direction Inbound -Protocol UDP -LocalPort 1520 -Action Block

Related ports

1518vpvd1519vpvc1521Oracle Database listener1522ricardo-lm

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