I write this tutorial to show how it is simple wakup a PC through Internet using WOL feature. What is WOL feature? Wake-on-LAN (WOL) is an Ethernet computer networking standard that allows a computer to be turned on or woken up by a network message. The message is usually sent by a program executed on another computer on the same local area network. It is also possible to initiate the message from another network by using Subnet directed broadcasts or a WOL gateway service. Wake-on-LAN is implemented using a special network message called a magic packet. The magic packet contains [...]

How long does it take to reload your router? 3 or 4 minutes? Do you know that is possible to speed up your reboot? If your answer is negative, read how warm reload is faster than cold (classic) reload. Introduced in Cisco IOS Release 12.3(2)T, the warm reload feature allows users to reload their routers without reading images from storage. That is, the Cisco IOS image reboots without ROM monitor mode (ROMMON) intervention by restoring the read-write data from a previously saved copy in the RAM and by starting execution without either copying the image from flash to RAM or [...]

Not everyone knows that the reload command permits to schedule a reboot system; for instance, to plan a night router restart or during a critical configuration (AAA, vty, and so on…). There are two ways to schedule a reload system: at: at a specific time/date in: after a time interval The ‘at’ keyword permits to schedule a reload of the software to take place at the specified time (using a 24-hour clock). If you specify the month and day, the reload is scheduled to take place at the specified time and date. The following example reloads the router on April [...]

There are many tools to decrypt Cisco type-7 password, based on Vigenere algorithm. But, what can we do if we can not use these software? The Cisco-IOS method might not be new to some, but those that don’t know about it will find it useful. Suppose you would decrypt these string: username cisco password 7 0718365B000A1016141D11050A2F6527273E username fabio password 7 0110140558004B0224014600110C To find the password, you can use the Cisco Key Chain:

An access list is a sequential list consisting of at least one permit statement and possibly one or more deny statements that apply to IP addresses and possibly upper-layer IP protocols. Time-based ACLs is a Cisco feature introduced in the Release 12.0.1.T to allow access control based on time. The time range, identified by a name, can be ‘absolute‘ or ‘periodic‘. Use time-based access list is easy and can be useful in some situations. To implement it, you need: Define time-range Define ACL, where the time-range is applied to Apply ACL; for istance: to the interface, to the vty, to [...]

Traceroute is a tool for measuring the route path and transit times of packets across an Internet Protocol (IP) network. Traceroute sends a sequence of Internet Control Message Protocol (ICMP) packets addressed to a destination host. Tracing the intermediate routers traversed involves control of the time-to-live (TTL) Internet Protocol parameter. Routers decrement this parameter and discard a packet when the TTL value has reached zero, returning an ICMP error message (ICMP Time Exceeded) to the sender. In a Data Center, it is often required to find a host and the layer2 path. To do it, Cisco has implemented a good [...]

What can I do if I forgot the password in my router? The fastest solution is replace it with the ‘password recovery‘ (you can try to find the password with bruteforce attack but I think it is not the better solution..). During the password recovery procedure, it is fundamental sent the correct ‘Break’ key sequence to enable ROMMON, but, as you know, the ‘break’ sequence depends by the software that you use! Below the standard break key sequence combinations for the most common operating systems.

The origins of regular expressions lie in automata theory and formal language theory, both of which are part of theoretical computer science. These fields study models of computation (automata) and ways to describe and classify formal languages. In the 1950s, mathematician Stephen Cole Kleene described these models using his mathematical notation called regular sets. The SNOBOL language was an early implementation of pattern matching, but not identical to regular expressions. Ken Thompson built Kleene’s notation into the editor QED as a means to match patterns in text files. A regular expression is entered as part of a command and is [...]

A number of shortcuts exist within the IOS command line interface. The most famous shortcut is the ‘TAB’ command, that completes a partially typed CLI command. For istance, if you type “sh ru” and press TAB, it will complete the command as “show running-config“. Below the complete list of the IOS shortcuts: Ctrl+T: Swap the current character with the one before it Ctrl+K: Erase all characters from the current cursor position to the end of the line Ctrl+X: Erase all characters from the current cursor position to the beginning of the line Ctrl+L: Reprint the line Ctrl+C: Exit configuration mode

Recently, I have upgraded my Cisco 2650XM from 12.3 to 12.4 version; I use it to connect my PC to Internet, but something goes wrong. After the upgrading, I have tried to downlad an ISO image but the speed was very low (about 300KB/s and not 700KB/s). Mhhh this is strange! I have begun the troubleshooting but no error, no warning message. So I have reset my current configuration, but nothing… no real improvement.