10 Cisco Logging Levels Best Practices

Logging is a critical part of network administration. It provides visibility into network activity and can be used to troubleshoot issues. Cisco devices generate a lot of log data, and it can be overwhelming to try to sift through all of it.

To help you get the most out of Cisco logging, we’ve put together a list of 10 best practices. By following these best practices, you can more effectively use Cisco logging to troubleshoot issues and monitor your network.

1. Enable logging

If you don’t enable logging, you will have no record of what has happened on your network. This can make it very difficult to troubleshoot problems, as you will have no way of knowing what changes were made or when they were made.

Enabling logging also allows you to monitor your network for unusual activity. If you see something suspicious, you can investigate further and take appropriate action.

Finally, logging can help you track down the source of security breaches. If you have a record of all activity on your network, you can more easily identify where the breach occurred and take steps to prevent it from happening again.

2. Configure a syslog server

A syslog server is a centralized location to store all of your log data. This is important because it provides a single place to go to look for issues and trends. It also allows you to offload the storage of log data from your devices, which can free up valuable resources.

Configuring a syslog server is not difficult, but there are a few things to keep in mind. First, you need to decide where you want to store your logs. There are many options available, both on-premises and in the cloud. Second, you need to choose a protocol. The two most common protocols are UDP and TCP. Each has its own advantages and disadvantages, so you’ll need to decide which one is right for your environment.

Once you’ve decided on a location and protocol, you can configure your devices to send their logs to the syslog server. Cisco devices have a built-in syslog server that can be configured with just a few clicks.

3. Use the right severity level

If you use the wrong severity level, it can result in two main problems. The first is that you’ll miss important events because they’ll be buried in low-severity logs. The second is that you’ll be overloaded with high-severity logs, making it difficult to find the needle in the haystack.

To avoid these problems, make sure you understand the different Cisco logging levels and use them appropriately. Here’s a quick overview of each level:

emergency: This is the highest severity level and is used for critical messages that require immediate attention.
alert: This severity level is used for messages that indicate a potential problem.
critical: This severity level is used for messages that indicate a serious problem.
error: This severity level is used for messages that indicate an error.
warning: This severity level is used for messages that indicate a warning.
notification: This severity level is used for messages that provide information about normal operation.
information: This is the lowest severity level and is used for messages that provide general information.

4. Log to multiple destinations

If you’re only logging to a single destination, and that destination fails, you’ve lost all your logs. But if you’re logging to multiple destinations, the failure of one destination doesn’t mean you’ve lost all your logs.

There are many different ways to log to multiple destinations. One way is to use a syslog server with failover capabilities. That way, if the primary syslog server goes down, the secondary syslog server takes over.

You can also configure Cisco devices to log to multiple syslog servers at the same time. That way, even if one syslog server goes down, the other syslog servers will still have a copy of the logs.

Finally, you can use a logging solution that supports high availability, such as Splunk Enterprise. Splunk Enterprise can replicate data across multiple instances, so if one instance goes down, the others can take over.

5. Disable console logging

Console logging sends all log messages to the router console port. This can quickly fill up your system memory and cause issues. Additionally, anyone who has physical access to the router can view the log messages, which could include sensitive information.

Instead of console logging, send log messages to a remote syslog server. This way, you can still view the logs, but they’re not stored on the router and they’re more secure.

6. Filter your logs

If you’re not filtering your logs, you’re likely overwhelmed with data and struggling to find the information you need. By filtering your logs, you can focus on the data that’s most important to you and make it easier to find what you’re looking for.

There are a few different ways to filter your logs. One is to use Cisco’s Logging Filter feature, which allows you to specify which types of events you want to see in your logs.

You can also use a third-party log management tool to filter your logs. This can be especially helpful if you have multiple devices and want to centralize your logging data.

Whatever method you choose, filtering your logs is an important best practice that will help you get the most out of your logging data.

7. Review your logs regularly

If you’re not reviewing your logs regularly, you could be missing important information about what’s happening on your network. Logs can contain information about attacks, configuration changes, and other events that can help you troubleshoot problems or improve your security posture.

Additionally, review your logs periodically to ensure that the logging levels are set appropriately for your environment. If the logging level is too low, you might miss important information. If the logging level is too high, you might overwhelm your system and make it difficult to find the information you need.

8. Use an alerting system

If you’re not using an alerting system, you’re likely missing out on critical information. That’s because the default logging levels for many Cisco devices are set to “warnings” or “errors,” which means that only messages at those levels will be logged.

However, there are often other important messages that are logged at lower levels, such as “informational” or “debug.” These messages can provide valuable insights into what is happening on your network, and they can help you troubleshoot problems more quickly.

An alerting system can help you make sure that you’re seeing all of the important messages by sending them to you in real-time, regardless of their logging level. This way, you can take action quickly if something goes wrong.

9. Automate log analysis

When you’re troubleshooting a network issue, the last thing you want to do is manually sift through log files. Not only is this time-consuming, but it’s also prone to error.

Instead, use a log analysis tool that can automatically parse and analyze your Cisco logs. This will not only save you time, but it will also help you spot issues that you might otherwise miss.

There are many different log analysis tools on the market, so be sure to do your research to find one that meets your specific needs.

10. Archive and store your logs

If you’re not storing your logs, you’re essentially throwing away valuable data that could be used to troubleshoot issues, track down security threats, and more. Not to mention, if you ever need to refer back to a past event, you won’t have any record of it if you’re not storing your logs.

There are a few different ways you can store your logs, but one of the best is to use a logging server. A logging server will allow you to centralize your logs in one place, which makes them easier to manage and search through. Additionally, many logging servers come with features like alerts and reporting, which can further help you make use of your log data.