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Port 8900 (jmb-cds1)

IANA assigns port 8900 to jmb-cds1: JMB-CDS 1.

Registered (user) port, 1024-49151 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference
jmb-cds1 TCP JMB-CDS 1 Curtis Bray -
jmb-cds1 UDP JMB-CDS 1 Curtis Bray -

Check what is listening on port 8900

Linux: is anything listening on TCP 8900?
sudo ss -tlnp 'sport = :8900'
Linux: UDP 8900
sudo ss -ulnp 'sport = :8900'
Linux / macOS: which process owns the port
sudo lsof -nP -i :8900
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':8900 '
Windows (Command Prompt)
netstat -ano | findstr :8900
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 8900 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 8900
From Windows
Test-NetConnection HOST -Port 8900
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 8900

Block port 8900 in the firewall

ufw
sudo ufw deny 8900/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 8900 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 8900 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 8900' -Direction Inbound -Protocol TCP -LocalPort 8900 -Action Block
ufw
sudo ufw deny 8900/udp
iptables
sudo iptables -A INPUT -p udp --dport 8900 -j DROP
nftables
sudo nft add rule inet filter input udp dport 8900 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 8900' -Direction Inbound -Protocol UDP -LocalPort 8900 -Action Block

Related ports

8894ddi-tcp-7, ddi-udp-78899ospf-lite8901jmb-cds28908dpp

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