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Port 4870 (cc-tracking)

IANA assigns port 4870 to cc-tracking: Citcom Tracking Service.

Registered (user) port, 1024-49151 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference
cc-tracking TCP Citcom Tracking Service Wolfgang Weidner -
cc-tracking UDP Citcom Tracking Service Wolfgang Weidner -

Registry dates for this port: registered 2005-12.

Check what is listening on port 4870

Linux: is anything listening on TCP 4870?
sudo ss -tlnp 'sport = :4870'
Linux: UDP 4870
sudo ss -ulnp 'sport = :4870'
Linux / macOS: which process owns the port
sudo lsof -nP -i :4870
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':4870 '
Windows (Command Prompt)
netstat -ano | findstr :4870
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 4870 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 4870
From Windows
Test-NetConnection HOST -Port 4870
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 4870

Block port 4870 in the firewall

ufw
sudo ufw deny 4870/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 4870 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 4870 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 4870' -Direction Inbound -Protocol TCP -LocalPort 4870 -Action Block
ufw
sudo ufw deny 4870/udp
iptables
sudo iptables -A INPUT -p udp --dport 4870 -j DROP
nftables
sudo nft add rule inet filter input udp dport 4870 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 4870' -Direction Inbound -Protocol UDP -LocalPort 4870 -Action Block

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Assignment data: IANA port number registry (public domain), retrieved 2026-11-10.