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Port 536 (opalis-rdv)

IANA assigns port 536 to opalis-rdv.

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

IANA assignment

Service nameProtoDescriptionAssigneeReference
opalis-rdv TCP opalis-rdv Laurent Domenech -
opalis-rdv UDP opalis-rdv Laurent Domenech -

Check what is listening on port 536

Linux: is anything listening on TCP 536?
sudo ss -tlnp 'sport = :536'
Linux: UDP 536
sudo ss -ulnp 'sport = :536'
Linux / macOS: which process owns the port
sudo lsof -nP -i :536
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':536 '
Windows (Command Prompt)
netstat -ano | findstr :536
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 536 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 536
From Windows
Test-NetConnection HOST -Port 536
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 536

Block port 536 in the firewall

ufw
sudo ufw deny 536/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 536 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 536 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 536' -Direction Inbound -Protocol TCP -LocalPort 536 -Action Block
ufw
sudo ufw deny 536/udp
iptables
sudo iptables -A INPUT -p udp --dport 536 -j DROP
nftables
sudo nft add rule inet filter input udp dport 536 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 536' -Direction Inbound -Protocol UDP -LocalPort 536 -Action Block

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