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Port 2101 (rtcm-sc104)

IANA assigns port 2101 to rtcm-sc104.

Registered (user) port, 1024-49151 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference
rtcm-sc104 TCP rtcm-sc104 Wolfgang Rupprecht -
rtcm-sc104 UDP rtcm-sc104 Wolfgang Rupprecht -

Check what is listening on port 2101

Linux: is anything listening on TCP 2101?
sudo ss -tlnp 'sport = :2101'
Linux: UDP 2101
sudo ss -ulnp 'sport = :2101'
Linux / macOS: which process owns the port
sudo lsof -nP -i :2101
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':2101 '
Windows (Command Prompt)
netstat -ano | findstr :2101
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 2101 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 2101
From Windows
Test-NetConnection HOST -Port 2101
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 2101

Block port 2101 in the firewall

ufw
sudo ufw deny 2101/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 2101 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 2101 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 2101' -Direction Inbound -Protocol TCP -LocalPort 2101 -Action Block
ufw
sudo ufw deny 2101/udp
iptables
sudo iptables -A INPUT -p udp --dport 2101 -j DROP
nftables
sudo nft add rule inet filter input udp dport 2101 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 2101' -Direction Inbound -Protocol UDP -LocalPort 2101 -Action Block

Related ports

2099h2250-annex-g2100amiganetfs2102zephyr-srv2103zephyr-clt

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