Port111— rpcbind / portmapper
TCP/UDP 111 is the ONC RPC portmapper (rpcbind). RPC services such as NFS register here, and clients query 111 to discover the actual service ports. It almost always appears alongside NFS (2049).
Registry assignments, software defaults and local listeners are different things. A port number alone does not identify or secure a service.
Configuration and troubleshooting
For NFS mount failures: allow 111 (TCP and UDP) plus 2049 on both ends. mountd, statd and lockd use dynamic ports — list them with `rpcinfo -p <server>` and pin them in your firewall. Machines that never use NFS can disable rpcbind outright: `systemctl disable --now rpcbind`.
Important limitations
Port 111 on a public IP lets scanners enumerate RPC services and has been abused for DDoS amplification. Disable it unless you serve NFS/RPC; otherwise restrict sources with a firewall.
Read-only checks: run on the server host
Choose the commands for your OS. Check TCP and UDP separately. No result is not a lasting availability guarantee; inspect host and container separately.
Linux
sudo ss -ltnp 'sport = :111'
sudo ss -lunp 'sport = :111'macOS
sudo lsof -nP -iTCP:111 -sTCP:LISTEN
sudo lsof -nP -iUDP:111Windows PowerShell
Get-NetTCPConnection -LocalPort 111 -State Listen
Get-NetUDPEndpoint -LocalPort 111Sources and review
Sources checked on:
This review covers the explanations and sources on this page, not your device or every community software entry below.
Software Using This Port (3 software)
Community software entries: links are references, not individual verification.
RPC Port Mapper
RemotePortService
Usage Suggestions
- Before using port 111, please confirm it is not occupied by other services
- If you encounter port conflicts, consider using other ports or stopping the occupying service
Frequently asked questions
What is port 111 used for?
Port 111 sits in the Others category. This page lists the registered purpose and the software commonly associated with it; to see what is actually listening on a specific machine, check the process with ss/netstat.
Is port 111 TCP or UDP?
The registered protocol on this page is TCP / UDP. The same number behaves independently on each protocol: TCP may be listening while UDP is idle, so check them separately.
How do I check if port 111 is in use?
On Linux: sudo ss -tlnp 'sport = :111' for an exact port match. On macOS: sudo lsof -nP -iTCP:111 -sTCP:LISTEN. On Windows PowerShell: Get-NetTCPConnection -LocalPort 111 -State Listen. A listener counts as confirmed only when you can see the bind address and process name; without root/admin you will not see other users' processes.
Is port 111 secure? Should I open it in my firewall?
A port number has no inherent security — it depends on whether the listening service is correctly configured and whether it needs exposure at all. Keep loopback/internal-only services firewalled; where public access is required, pair it with source restrictions, VPN or authentication. The caution section on this page lists port-specific risks.
Quick Info
- Port
- 111
- Protocol
- TCP/UDP
- Categories
- Others
- Usage Status
- 3 software in use
Related Ports
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