HTTPfy

Port 1686 (cvmon)

IANA assigns port 1686 to cvmon.

Registered (user) port, 1024-49151 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference
cvmon TCP cvmon Carol Ann Krug -
cvmon UDP cvmon Carol Ann Krug -

Check what is listening on port 1686

Linux: is anything listening on TCP 1686?
sudo ss -tlnp 'sport = :1686'
Linux: UDP 1686
sudo ss -ulnp 'sport = :1686'
Linux / macOS: which process owns the port
sudo lsof -nP -i :1686
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':1686 '
Windows (Command Prompt)
netstat -ano | findstr :1686
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 1686 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 1686
From Windows
Test-NetConnection HOST -Port 1686
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 1686

Block port 1686 in the firewall

ufw
sudo ufw deny 1686/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 1686 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 1686 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 1686' -Direction Inbound -Protocol TCP -LocalPort 1686 -Action Block
ufw
sudo ufw deny 1686/udp
iptables
sudo iptables -A INPUT -p udp --dport 1686 -j DROP
nftables
sudo nft add rule inet filter input udp dport 1686 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 1686' -Direction Inbound -Protocol UDP -LocalPort 1686 -Action Block

Related ports

1684snaresecure1685n2nremote1687nsjtp-ctrl1688nsjtp-data

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