When Can not login S5700 after S5700 power on?

By | February 7, 2017

Issue Description

After a customer upgraded the software version to V200R005C00SPC500 and the latest patch V200R005SPH011 from V200R005C00SPC200, he could login S5700 by telnet. Then the S5700 was powered off due to power outage. After he powered on S5700 again, he couldn’t login S5700 by telnet.

The topology is simple:

 

Here are the detail steps:

(1)   In the old software version V200R005C00SPC200, the customer can login S5700 by telnet.

(2)   After a customer upgraded the software version to V200R005C00SPC500 and the latest patch V200R005SPH011, he can login S5700 by telnet. When he checked the configuration, he found the following configuration, which didn’t exist in the configuration of V200R005C00SPC200.

#

telnet server enable

#

user-interface vty 0 4

protocol inbound telnet

#

 

(3)   But then S5700 was powered off due to power outage. After S5700 was powered on again, the customer couldn’t login S5700 by telnet. When he login S5700 by console interface, he found the there was no above configuration.

Alarm Information

None

Handling Process

(1)   After the S5700 was power on, the customer login S5700 by console interface, then he added the following configuration, he can login S5700 again by telnet.

#

telnet server enable

#

user-interface vty 0 4

protocol inbound telnet

#

Root Cause

(1)  In V200R005C00SPC200, the telnet server is enabled by default. So in the configuration of SPC200, there is no such command “telnet server enable” by default, but you can login S5700 by telnet.

(2)    In V200R005C00SPC500, the telnet server is disabled by default.  So in the configuration of SPC500, if there is no command “telnet server enable”, you can’t login S5700 by telnet.

(3)   During the upgrade of  S5700 from SPC200 to SPC500+patch V200R005SPH011,  S5700 will do this configuration translation. (it found that the last software version is SPC200, but the new one is SPC500, so it will do the configuration translation)

(4)   So when S5700 is running with SPC500 for the first time, in the current running configuration, you can see “telnet server enable”, and you can login S5700 by telnet. But in the saved  configuration, it’s still the  same configuration as SPC200 where there is no such command “telnet server enable”.

In this situation,

(1.1)    If the configuration was not “save”, after S5700 was rebooted( by manually, by power on-off button or by power outage) again, the  S5700 will not do the configuration translation again, and will run with that configuration which was used in SPC200, and for this configuration, there is no “telnet server enable”. But for SPC500, if there is no “telnet server enable” in the running configuration, you can’t login S5700 by telnet.

(1.2)    If the configuration was  “save”, the command “telnet server enable” will be saved to the saved configuration.  After S5700 is rebooted again, in the running configuration, there is ““telnet server enable”, so you can login S5700 by telnet.

Solution

(1)   After the software version of S5700 was upgraded to V200R005C00SPC500 and the latest patch V200R005SPH011 from V200R005C00SPC200, you need “save” the current configuration.

(2) Or you need configure the following commands for telnet.

#

telnet server enable

#

user-interface vty 0 4

protocol inbound telnet

#

Suggestions

After the software version of S5700 was upgraded to V200R005C00SPC500 and the latest patch V200R005SPH011 from V200R005C00SPC200, you need “save” the current configuration.  If not, after S5700 was rebooted or power on again, you can’t login S5700 by telnet.

 

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