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Port 5137 (ctsd)

IANA assigns port 5137 to ctsd: MyCTS server port.

Registered (user) port, 1024-49151 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference
ctsd TCP MyCTS server port Jilles Oldenbeuving -
ctsd UDP MyCTS server port Jilles Oldenbeuving -

Registry dates for this port: registered 2002-06.

Check what is listening on port 5137

Linux: is anything listening on TCP 5137?
sudo ss -tlnp 'sport = :5137'
Linux: UDP 5137
sudo ss -ulnp 'sport = :5137'
Linux / macOS: which process owns the port
sudo lsof -nP -i :5137
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':5137 '
Windows (Command Prompt)
netstat -ano | findstr :5137
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 5137 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 5137
From Windows
Test-NetConnection HOST -Port 5137
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 5137

Block port 5137 in the firewall

ufw
sudo ufw deny 5137/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 5137 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 5137 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 5137' -Direction Inbound -Protocol TCP -LocalPort 5137 -Action Block
ufw
sudo ufw deny 5137/udp
iptables
sudo iptables -A INPUT -p udp --dport 5137 -j DROP
nftables
sudo nft add rule inet filter input udp dport 5137 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 5137' -Direction Inbound -Protocol UDP -LocalPort 5137 -Action Block

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5135erp-scale5136minotaur-sa5145rmonitor-secure, rmonitor_secure5146social-alarm

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