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Port 4989 (parallel)

IANA assigns port 4989 to parallel: Parallel for GAUSS (tm).

Registered (user) port, 1024-49151 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference
parallel TCP Parallel for GAUSS (tm) Matthew Ford -
parallel UDP Parallel for GAUSS (tm) Matthew Ford -

Registry dates for this port: registered 2003-03.

Check what is listening on port 4989

Linux: is anything listening on TCP 4989?
sudo ss -tlnp 'sport = :4989'
Linux: UDP 4989
sudo ss -ulnp 'sport = :4989'
Linux / macOS: which process owns the port
sudo lsof -nP -i :4989
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':4989 '
Windows (Command Prompt)
netstat -ano | findstr :4989
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 4989 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 4989
From Windows
Test-NetConnection HOST -Port 4989
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 4989

Block port 4989 in the firewall

ufw
sudo ufw deny 4989/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 4989 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 4989 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 4989' -Direction Inbound -Protocol TCP -LocalPort 4989 -Action Block
ufw
sudo ufw deny 4989/udp
iptables
sudo iptables -A INPUT -p udp --dport 4989 -j DROP
nftables
sudo nft add rule inet filter input udp dport 4989 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 4989' -Direction Inbound -Protocol UDP -LocalPort 4989 -Action Block

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4987smar-se-port14988smar-se-port24990busycal4991vrt

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