Syslog messages that appear on a Cisco device consists of several parts. Consider the following message: *Jan 18 03:02:42: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet0/0, changed state to down The message consists of the following parts: Jan 18 03:02:42 – Read More …
Author: upravnik
Syslog explained
Syslog is a standard for message logging. Syslog messages are generated on Cisco devices whenever an event takes place – for example, when an interface goes down or a port security violation occurs. You’ve probably already encountered syslog messages when Read More …
Auxiliary Port on a Cisco router
Most Cisco routers include an additional auxiliary (Aux) port as a backup async port. This port is commonly used as a dial-up port for remote router management. It is connected to a modem and enables an administrator to make a Read More …
Interface status codes
Interface status codes can tell you whether an interface on a Cisco router or a switch is working. Status codes of an interface can be displayed using the show interface TYPE command, e.g.: SW1#show interface fa0/1 FastEthernet0/1 is up, line Read More …
DHCP relay agent
When a device is configured as a DHCP client, it will send a a broadcast packet to discover DHCP servers on the network. Broadcast packets are not forwarded by routers by default, so if a DHCP server is in a Read More …
Configure timezone and Daylight Saving Time (DST)
It is recommended to set the correct timezone and adjust the DST setting before configuring a router as an NTP client. The syntax of the command used to set the timezone is: (config)clock timezone NAME HOURS [MINUTES] The name of Read More …
Default static route
A default route defines where packets will be sent if no specific route for the destination network is listed in the routing table. If no default route is set, the router will discard all packets with destination addresses not found Read More …
The ARP table on a Cisco router
Just like regular hosts, if a Cisco router wants to exchange frames with a host in the same subnet, it needs to know its MAC address. The IP-to-MAC address mapping are kept in the router’s ARP table. Consider the following Read More …
Uniform Resource Locator (URL) structure
An URL is a string of characters that contains information about how to fetch a resource from its location. An URL specifies the primary access mechanism and the network location of a resource. A typical URL consists of the following Read More …
Create a static host route
In one of the previous lessons we’ve defined a static route for a specific subnet by using the subnet mask of 255.255.255.0 in the ip route command. IOS also allows you to specify a static host route for a single Read More …