How to Enable Telnet Access Using Router Local Username/Password Database?

350-401 By islever Editorial Last updated

Short answer

D RouterX(config)# line vty 0 4 -

Question

An administrator must enable Telnet access to Router X using the router username and password database for authentication. Which configuration should be applied?
  1. RouterX(config)# line aux 0 -
  2. RouterX(config)# aaa new-model -
  3. RouterX(config)# line vty 0 4 -
  4. RouterX(config)# line vty 0 4 - Correct Answer

Key Takeaways

This question tests your understanding of management plane access methods, specifically that VTY lines are the virtual terminal lines used for Telnet and SSH. The common trap is to mistake global AAA configuration or auxiliary port setup for VTY-level local authentication.

The correct configuration for enabling Telnet access with a router's local username/password database centers on the VTY lines. The Cisco community agrees that answer D is the intended choice, with follow-up commands like 'login local' and 'transport input telnet' being essential for a complete implementation.

Common mistake: The most common wrong answer is A ('line aux 0') or B ('aaa new-model'). A targets the auxiliary port, which is not used for Telnet; B only enables the AAA framework and does not configure local login on VTY lines. Both lack the necessary VTY context and the 'login local' command.

Expert Analysis

Why the Answer Is Correct

VTY lines are the virtual terminal lines that handle Telnet, SSH, and other remote management protocols. To authenticate users against the local username/password database, you must enter VTY line configuration mode and issue 'login local'. Option D specifically points to 'line vty 0 4', which is the correct line for Telnet access. Community comments emphasize that 'login local' is the critical command under the VTY lines to use the local database.

Why the Other Options Are Wrong

Option A targets the auxiliary line ('line aux 0'), which is used for modem console management, not Telnet. Option B ('aaa new-model') is a global command that enables AAA services, but by itself it does not configure authentication for VTY lines. Options C and D are presented with identical text, but the intended correct answer is D because it correctly identifies the need to configure VTY lines; the other options do not provide any method for local authentication.

Community Comment Notes

Comment [1] plainly states 'D | login → password login local → username + password', indicating the standard VTY configuration needed. Comment [2] clarifies that on newer IOS versions (e.g., 17.1) you may also need to explicitly enable Telnet with 'transport input telnet' or 'all', while older devices had it enabled by default. Comment [3] confirms that many search results show Telnet on by default, but in CML with IOS 15.9 the default is 'transport input none', so candidates must consider the IOS version — but for the exam, selecting the VTY line is the core action.

Exam Strategy

When asked about enabling Telnet or SSH with local authentication, immediately eliminate any answer that doesn't reference VTY lines. Then ensure the answer includes or implies 'login local' under the VTY configuration; if the options are incomplete, choose the one that correctly identifies the VTY context as the necessary starting point.

Community Votes

D
100%

100% of anonymous learners picked answer D. Votes are pick records left by other test-takers — they are not the verified answer.

Discussion 3 contributions

Compiled from public community threads and reader submissions, lightly edited for clarity. Handles and vote tallies are shown as recorded, and comments reflect the views of individual contributors.

From public community threads 3

  1. chiacche 👍 5 Answered D
    login → password login local → username + password
  2. NetworkJanitor 👍 1 Answered D
    It's D, but the answer is not complete. Telnet would have be enabled on newer code like 17.1. For older gear it was enabled out of the box. CAT9-UADP_2(config-line)#login local ? <cr> <cr> CAT9-UADP_2(config-line)#login local CAT9-UADP_2(config-line)#do sh run | i transport input (show defaults) transport input ssh transport input ssh CAT9-UADP_2(config-line)# CAT9-UADP_2(config-line)#transport input ? all All protocols none No protocols ssh TCP/IP SSH protocol telnet TCP/IP Telnet protocol // hth
  3. NetworkJanitor 👍 1 Answered D
    Most search returns show that Telnet is on by default with Cisco. So, D would be the nearest to true answer. However, in CML with newer code, no transport is set: R20#more system:default-running-config | s transport mode transport transport input none <------------ R20#sh ver | s Version Cisco IOS Software, IOSv Software (VIOS-ADVENTERPRISEK9-M), Version 15.9(3)M8, RELEASE SOFTWARE (fc1) R20#

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