HTTPfy

Port 40843 (csccfirewall)

IANA assigns port 40843 to csccfirewall: CSCCFIREWALL.

Registered (user) port, 1024-49151 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference
csccfirewall TCP CSCCFIREWALL Sudhir Menon -
csccfirewall UDP CSCCFIREWALL Sudhir Menon -

Check what is listening on port 40843

Linux: is anything listening on TCP 40843?
sudo ss -tlnp 'sport = :40843'
Linux: UDP 40843
sudo ss -ulnp 'sport = :40843'
Linux / macOS: which process owns the port
sudo lsof -nP -i :40843
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':40843 '
Windows (Command Prompt)
netstat -ano | findstr :40843
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 40843 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 40843
From Windows
Test-NetConnection HOST -Port 40843
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 40843

Block port 40843 in the firewall

ufw
sudo ufw deny 40843/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 40843 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 40843 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 40843' -Direction Inbound -Protocol TCP -LocalPort 40843 -Action Block
ufw
sudo ufw deny 40843/udp
iptables
sudo iptables -A INPUT -p udp --dport 40843 -j DROP
nftables
sudo nft add rule inet filter input udp dport 40843 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 40843' -Direction Inbound -Protocol UDP -LocalPort 40843 -Action Block

Related ports

40841cscp40842csccredir40853ortec-disc41111fs-qos

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