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Port 23053 (gntp)

IANA assigns port 23053 to gntp: Generic Notification Transport Protocol.

Registered (user) port, 1024-49151 TCP

IANA assignment

Service nameProtoDescriptionAssigneeReference
gntp TCP Generic Notification Transport Protocol Growl Project -

Registry dates for this port: registered 2012-02-07.

Check what is listening on port 23053

Linux: is anything listening on TCP 23053?
sudo ss -tlnp 'sport = :23053'
Linux / macOS: which process owns the port
sudo lsof -nP -i :23053
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':23053 '
Windows (Command Prompt)
netstat -ano | findstr :23053
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 23053 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 23053
From Windows
Test-NetConnection HOST -Port 23053

Block port 23053 in the firewall

ufw
sudo ufw deny 23053/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 23053 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 23053 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 23053' -Direction Inbound -Protocol TCP -LocalPort 23053 -Action Block

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Assignment data: IANA port number registry (public domain), retrieved 2026-11-10.