When we use Huawei NE series routers, we sometimes encounter problems. How can these problems be solved? We provide the Troubleshooting Guide to help you.
If you encounter A User Fails to Log in to a Server Using Telnet, perform the following steps:
1. Check whether the Telnet client can ping the server.
Run the ping command to check network connectivity. If the ping fails, the Telnet connection cannot be established between the client and server.
2. Check whether the number of users logging in to the server has reached the upper threshold.
Log in to the server using a console interface and run the display users command to check whether all the available VTY channels are used. By default, a maximum of 5 users can log in to the server through VTY channels.
<HUAWEI> display user-interface maximum-vty
Maximum of VTY user:5
<HUAWEI> display users
User-Intf Delay Type Network Address AuthenStatus AuthorcmdFlag
+ 0 CON 0 00:00:01 Username : Unspecified
34 VTY 0 02:11:28 TEL 10.138.81.61 pass yes Username : huawei
If the number of users logging in to the server has reached the upper threshold, run the user-interface maximum-vty vty-number command to increase the maximum number of users allowed to log in to the server through VTY channels to 18.
<HUAWEI> system-view
[~HUAWEI] user-interface maximum-vty 18
3. Check whether an ACL with a deny rule is configured in the VTY user interface view.
If an ACL rule has already been bound to VTY user interfaces, verify that the configured ACL rule does not deny IP addresses, port numbers, or protocol numbers of clients.
4. Check whether the access protocol configured in the VTY user interface view is correct.
[~HUAWEI] user-interface vty 0 4
[~HUAWEI-ui-vty0-4] display this
user-interface vty 0 4
authentication-mode aaa
user privilege level 3
idle-timeout 0 0
protocol inbound ssh
Run the protocol inbound { all | ssh | telnet } command to configure the user access protocol. Telnet is an insecure protocol. SSH is recommended.
§ If the user access protocol is set to SSH, the user cannot log in to the server using Telnet.
§ If the user access protocol is set to "all", the user can log in to the server using Telnet or SSH.
5. Check whether the authentication mode is configured in the user interface view.
§ If the authentication-mode password command is run, the login authentication mode in the VTY channel is set to password.
§ If the authentication-mode aaa command is run, the login authentication mode is set to aaa. You must run the local-user password command to add a local user.
6. Collect the following information and contact Huawei technical support personnel.
§ Results of the preceding troubleshooting procedures.
§ Configuration files, log files, and alarm files of the devices.
For more troubleshooting cases, see: NE40E Troubleshooting Guide V4.0 (VRPv8)
https://support.huawei.com/enterprise/en/doc/EDOC1000177634
