HTTPfy

Port 2723 (watchdog-nt)

IANA assigns port 2723 to watchdog-nt: WatchDog NT Protocol.

Registered (user) port, 1024-49151 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference
watchdog-nt TCP WatchDog NT Protocol Loftware -
watchdog-nt UDP WatchDog NT Protocol Loftware -

Registry dates for this port: last modified 2020-07-20.

Check what is listening on port 2723

Linux: is anything listening on TCP 2723?
sudo ss -tlnp 'sport = :2723'
Linux: UDP 2723
sudo ss -ulnp 'sport = :2723'
Linux / macOS: which process owns the port
sudo lsof -nP -i :2723
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':2723 '
Windows (Command Prompt)
netstat -ano | findstr :2723
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 2723 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 2723
From Windows
Test-NetConnection HOST -Port 2723
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 2723

Block port 2723 in the firewall

ufw
sudo ufw deny 2723/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 2723 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 2723 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 2723' -Direction Inbound -Protocol TCP -LocalPort 2723 -Action Block
ufw
sudo ufw deny 2723/udp
iptables
sudo iptables -A INPUT -p udp --dport 2723 -j DROP
nftables
sudo nft add rule inet filter input udp dport 2723 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 2723' -Direction Inbound -Protocol UDP -LocalPort 2723 -Action Block

Related ports

2721smart-diagnose2722proactivesrvr2724qotps2725msolap-ptp2

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