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Port 259 (esro-gen)

IANA assigns port 259 to esro-gen: Efficient Short Remote Operations.

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

IANA assignment

Service nameProtoDescriptionAssigneeReference
esro-gen TCP Efficient Short Remote Operations Mohsen Banan -
esro-gen UDP Efficient Short Remote Operations Mohsen Banan -

Check what is listening on port 259

Linux: is anything listening on TCP 259?
sudo ss -tlnp 'sport = :259'
Linux: UDP 259
sudo ss -ulnp 'sport = :259'
Linux / macOS: which process owns the port
sudo lsof -nP -i :259
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':259 '
Windows (Command Prompt)
netstat -ano | findstr :259
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 259 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 259
From Windows
Test-NetConnection HOST -Port 259
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 259

Block port 259 in the firewall

ufw
sudo ufw deny 259/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 259 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 259 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 259' -Direction Inbound -Protocol TCP -LocalPort 259 -Action Block
ufw
sudo ufw deny 259/udp
iptables
sudo iptables -A INPUT -p udp --dport 259 -j DROP
nftables
sudo nft add rule inet filter input udp dport 259 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 259' -Direction Inbound -Protocol UDP -LocalPort 259 -Action Block

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