Using NTP to synchronize the date and time of multiple devices makes sense even in a small network. When performing forensic analyses or troubleshooting connection problems, having consistent logging timestamps from multiple devices can save time and simplify the task.

Setting the internal clock in a Cisco router allows timestamping of logging information which makes troubleshooting much easier. If you do not have an NTP server running, you can set the time manually with a simple command.

The default source IP address when telnetting from a Cisco router is that of the interface closest to the destination. Because some access lists may block traffic from the default IP address, it may be useful to temporarily or permanently set the telnet source IP address. This also helps test access lists.

Multiple users can be logged into a Cisco router at the same time. It may be necessary (or sometimes just fun) to send a text message to one or all users on a router. For example, if you are preparing to reload the router, admin etiquette dictates that you should warn other users.

Wide area networks are often very wide, and installing or troubleshooting remote routers often requires fingers on keyboards in more than one physical location. Getting a listing of the users logged into a router is simple, which makes it easier to send that user a message (as many remote locations have no cell phone signal).

Centralizing log messages to a syslog server can improve the manageability of any size network and can decrease response times to resolve problems. Sending router log messages to a remote server also allows longer archiving of messages than in a router’s limited storage. Messages stored by syslog have permanence that a router does not. When […]

A router’s log can save your life. Well, at the least, it can save you time and headaches when troubleshooting problems. However, in the heat of battle, old messages in the log can get in the way. After making a change to the router’s configuration, for instance, it is easier to monitor only subsequent messages […]

Messages logged by a router can make troubleshooting problems substantially easier. However, the default size of most Cisco routers is 4096 bytes which typically accommodates fewer than 60 messages. While this may help in many situations, adding some additional space can save the day when a router generates frequent error messages as when an interface […]

When replacing a faulty router that is not completely dead, it may be possible to copy the startup configuration to the removable flash memory and swap the flash to get the new router up and configured in as short a time as possible. Without this procedure, manually copying the old configuration to the new router […]

Every active interface on a Cisco router to be used with IP requires an IP address be assigned to it. This short tech-recipe describes how to set an interface’s IP address.

I found an ancient 2500 series router today and had to go through a password recovery. The rommon version was earlier than any I had seen before. The help functionality was very lean. Here is how to set the confreg for these older models.

Cisco CallManager partitions and calling search spaces (CSS) are confusing. This Tech-Recipe describes how I keep track of how they work.