Three classic tricks to solve the switch's inability to manage remotely

As one of the core devices in the LAN, the performance of the switch directly determines the data transmission performance of the network. However, after a long period of work, the switch will inevitably encounter such or such a fault phenomenon, in order to solve the problem in time, network administrators often take a remote approach to manage the switching system.

However, sometimes, we will encounter the phenomenon of remote management of the switch, in the face of this phenomenon, what should we do to face it? Now, this article on the elimination of this type of failure analysis, hoping to bring some help to everyone.

Check Line connection Status

If the physical connection between the client system and the target switch device is not smooth, then of course we cannot remotely administer the target switch's backend management system via the network channel, so that when we encounter the inability to remotely manage the switch phenomenon, First you should use the ping command to test the unobstructed state of the physical connection line. Of course, before you ping the test operation, we must select a common client system that is on the same subnet as the target switch, and then ping to test whether the IP address of the switch device can ping properly, and if it does not ping properly, That means there may be a problem with the physical connection state; At this point, we can try to swap with other client systems to continue the ping command test to see if the IP address of the target switch can still be normal ping, if it has been unable to ping, the problem is likely to appear in the switch itself "body", For example, the port of the switch is not working properly, or the hardware performance of the switch is not stable, it may cause failure phenomenon that can not ping.

Of course, if we can ping the switch device's IP address from normal client systems, but cannot remotely manage the target switch device, the problem is mostly a soft fault on the switch, such as a lower version of the switch backend management system, or a network virus intrusion on the switch system.

Check Port working Status

Sometimes, a switch port by the large volume of data constantly impacting, it is easy to cause the corresponding port card CPU resources are heavily consumed, when the corresponding board card on all Exchange ports will appear suspended animation phenomenon, this time if we through these suspended animation Exchange Port ping switch device IP address, There will naturally be a failure to ping, and you will not succeed if you attempt to log on remotely.

To determine if the switching port is working properly, we can use the console control line to connect directly to the switch's control port, and log in as a system administrator into the switch system's admin interface and execute the string command "Display CPU" in the command line state of the interface. To view the CPU resource consumption of each block card of the switch, if the CPU consumption rate of a board card is found to be over 50%, then a switch port on the corresponding board may be impacted by large volume data continuously.

In order to be able to locate the destination failover port, we can insert the network cable into each switching port of the failover board, then ping the gateway address of the LAN in the view mode state of the corresponding switch port to see if the target gateway address can be ping normally. Once a switch port is found to be unable to ping the destination gateway address properly, we must execute the string command "Display XXX" in the view mode state of the switching port, where "XXX" is the specified Exchange port. We can clearly determine the input packet of the exchange port from the result interface that pops up afterwards, output packet, broadcast packet size, if you see the input packet, output packet size at the same time more than 1000m/s size, which means that the current Exchange port data flow is not normal. At this point, to prevent the switching port from continuing to affect the operating state of the entire switch, we must temporarily turn off the enabled state of the target failover port by taking advantage of the "shutdown" command that comes with the switch system, and then further look for the subnet status under the destination failover port. In order to create the switch board card CPU is excessive consumption of the real "sin", so as to restore the target switching port working state, so that we can be normal through the network to remotely manage the target switch.