HTTPfy

Port 8442 (cybro-a-bus)

IANA assigns port 8442 to cybro-a-bus: CyBro A-bus Protocol.

Registered (user) port, 1024-49151 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference
cybro-a-bus TCP CyBro A-bus Protocol Damir Skrjanec -
cybro-a-bus UDP CyBro A-bus Protocol Damir Skrjanec -

Registry dates for this port: registered 2007-05.

Check what is listening on port 8442

Linux: is anything listening on TCP 8442?
sudo ss -tlnp 'sport = :8442'
Linux: UDP 8442
sudo ss -ulnp 'sport = :8442'
Linux / macOS: which process owns the port
sudo lsof -nP -i :8442
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':8442 '
Windows (Command Prompt)
netstat -ano | findstr :8442
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 8442 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 8442
From Windows
Test-NetConnection HOST -Port 8442
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 8442

Block port 8442 in the firewall

ufw
sudo ufw deny 8442/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 8442 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 8442 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 8442' -Direction Inbound -Protocol TCP -LocalPort 8442 -Action Block
ufw
sudo ufw deny 8442/udp
iptables
sudo iptables -A INPUT -p udp --dport 8442 -j DROP
nftables
sudo nft add rule inet filter input udp dport 8442 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 8442' -Direction Inbound -Protocol UDP -LocalPort 8442 -Action Block

Related ports

8432pgbackrest8433aws-as28443HTTPS alternate8444pcsync-http

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