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// Remote access

Port 107: Remote Telnet Service

Port 107 is assigned by IANA to rtelnet (Remote Telnet Service).

107

How rtelnet works

Remote access
terminal:107rtelnet terminal:107rtelnet

The client opens a session to port 107: each command typed is sent to the server, which runs it and returns the output.

Transport
TCP · UDP
Exposure risk
not rated depends on the program listening
Encryption
Unknownnot stated by the registry
IANA status
Assigned1 registered service
Range
Well-known (0-1023)
Category
Remote access
01 Security

Is port 107 dangerous?

We have no specific security note for port 107. Its risk depends on the program actually listening on it. General advice for remote access services:

  • Do not expose remote administration directly: use a VPN or a zero-trust access proxy.
  • Require MFA or key-based authentication and lock out brute-force attempts.
  • Log every login and alert on new source addresses.
02 Registry

IANA registry entries for port 107

ServicePortTransportDescriptionReferenceUpdated
rtelnet 107 TCP, UDP Remote Telnet Service - -

// source: IANA service name and port number registry

03 Check it

Which program uses port 107, and is it reachable?

Linux

sudo ss -ltnup 'sport = :107'      # process listening on 107
sudo lsof -nP -i :107

macOS

sudo lsof -nP -i :107

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 107 -State Listen | Select LocalAddress, OwningProcess
Get-NetUDPEndpoint -LocalPort 107
netstat -ano | findstr :107

From another machine

nmap -p 107 -sV <host>
sudo nmap -sU -p 107 <host>
nc -zv <host> 107

Block it in the firewall

sudo ufw deny 107/tcp                                         # Linux (ufw)
New-NetFirewallRule -DisplayName "Block 107" -Direction Inbound -LocalPort 107 -Protocol TCP -Action Block  # Windows
04 FAQ
What is port 107 used for?

Port 107 is assigned by IANA to rtelnet (Remote Telnet Service).

Is port 107 TCP or UDP?

Port 107 is registered for TCP and UDP.

Is it safe to open port 107?

It depends on the program that listens on it. Open it only for a service you know and only to the networks that need it. Do not expose remote administration directly: use a VPN or a zero-trust access proxy.

How do I check if port 107 is open?

On Linux run "ss -ltnup 'sport = :107'", on macOS "lsof -nP -i :107", and on Windows "netstat -ano | findstr :107" to see the local process. From another machine, "nmap -p 107 <host>" shows whether it is reachable.

05 Related
:22 SSH tcp · udp · sctp · moderate risk :3389 RDP tcp · udp · critical risk :23 Telnet tcp · udp · critical risk :5900 VNC tcp · udp · critical risk :5985 WinRM (HTTP) tcp · udp · high risk :5986 WinRM (HTTPS) tcp · udp · high risk :10000 Webmin tcp · udp · high risk :89 SU/MIT Telnet Gateway tcp · udp

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