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Port 72 (netrjs-2)

IANA assigns port 72 to netrjs-2: Remote Job Service.

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

IANA assignment

Service nameProtoDescriptionAssigneeReference
netrjs-2 TCP Remote Job Service - -
netrjs-2 UDP Remote Job Service - -

Check what is listening on port 72

Linux: is anything listening on TCP 72?
sudo ss -tlnp 'sport = :72'
Linux: UDP 72
sudo ss -ulnp 'sport = :72'
Linux / macOS: which process owns the port
sudo lsof -nP -i :72
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':72 '
Windows (Command Prompt)
netstat -ano | findstr :72
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 72 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 72
From Windows
Test-NetConnection HOST -Port 72
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 72

Block port 72 in the firewall

ufw
sudo ufw deny 72/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 72 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 72 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 72' -Direction Inbound -Protocol TCP -LocalPort 72 -Action Block
ufw
sudo ufw deny 72/udp
iptables
sudo iptables -A INPUT -p udp --dport 72 -j DROP
nftables
sudo nft add rule inet filter input udp dport 72 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 72' -Direction Inbound -Protocol UDP -LocalPort 72 -Action Block

Related ports

70gopher71netrjs-173netrjs-374netrjs-4

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