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Port 9979 (visweather)

IANA assigns port 9979 to visweather: Valley Information Systems Weather station data.

Registered (user) port, 1024-49151 TCP

IANA assignment

Service nameProtoDescriptionAssigneeReference
visweather TCP Valley Information Systems Weather station data Valley Information Systems Inc -

Registry dates for this port: registered 2017-05-12.

Check what is listening on port 9979

Linux: is anything listening on TCP 9979?
sudo ss -tlnp 'sport = :9979'
Linux / macOS: which process owns the port
sudo lsof -nP -i :9979
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':9979 '
Windows (Command Prompt)
netstat -ano | findstr :9979
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 9979 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 9979
From Windows
Test-NetConnection HOST -Port 9979

Block port 9979 in the firewall

ufw
sudo ufw deny 9979/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 9979 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 9979 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 9979' -Direction Inbound -Protocol TCP -LocalPort 9979 -Action Block

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