Telnet Guide
Telnety includes a Telnet client for one reason only: there are still routers, switches, and serial-bridged industrial devices that speak nothing else. Every byte of a Telnet session — username, password, every command — travels the network in plaintext. Treat it that way.
When Telnet is acceptable
- Lab and isolated networks: air-gapped management VLANs where you control every hop.
- Initial setup of legacy hardware: some Cisco/HP/Aruba devices ship with Telnet enabled and no SSH host key generated yet.
- Console servers / terminal servers: reverse-Telnet to TCP ports 2000–2100 on devices like Cisco 2511 / Opengear / Lantronix.
Configuring a Telnet connection
When creating a new host, choose Telnet as the protocol:
- Hostname: IP address or FQDN of the target.
- Port: 23 by default. Use 2001–2100 for reverse-Telnet console servers.
- Encoding: UTF-8 by default. Use Latin-1 for older Cisco IOS / pre-1990s gear.
- Line mode: Off by default — local echo handled by the remote. Enable for half-duplex serial bridges.
Session recording
Telnet sessions can be recorded in Asciicast v2 format like any other terminal session. Because Telnet credentials travel in the clear, recordings will capture them too — Telnety strips obvious password prompts, but you should treat any Telnet recording as sensitive and store it accordingly.
Migrating to SSH
On most network gear, enabling SSH is a four-line config:
Once SSH is up, delete the Telnet host in Telnety and recreate it as SSH. See the SSH guide for key management and TOFU host-key pinning details.