Author Archives: Humair

Setup and Troubleshoot EIGRP

Posted on February 2, 2012 by Humair

I discussed Enhanced Interior Gateway Routing Protocol (EIGRP) briefly in a prior blog, Load Balancing with EIGRP, however, in this lab I use two Cisco 3725 routers [IOS 12.4(15)T10] to demonstrate how to configure EIGRP; additionally, I’ll discuss some useful … Continue reading →

Posted in Cisco, Labs, Networking, Protocols, Technology, Troubleshooting | Tagged Cisco, Cisco 3725, Cisco 3725 router, Cisco 3725 routers, dynamic routing, EIGRP, Enhanced Interior Gateway Routing Protocol, router | Leave a comment

Configuring PVST+ on Cisco Switches

Posted on February 1, 2012 by Humair

Per VLAN Spanning Tree Plus (PVST+) is a flavor of Spanning Tree Protocol (see prior blog, Default STP Behavior on Cisco Switches) which maintains a spanning tree instance for each VLAN in the network. This means certain VLAN trunks (using … Continue reading →

Posted in Cisco, Labs, Networking, Protocols, Technology | Tagged avoid loop, Cisco, Cisco 3560, Cisco 3560 switch, Cisco switch, dot1q, loop, Per VLAN Spanning Tree Plus, prevent loop, PVST+, Spanning Tree Protocol, STP, switch, vlan | 6 Comments

Default STP Behavior on Cisco Switches

Posted on January 31, 2012 by Humair

In a prior blog, Functionality of Layer 2 Switches/Bridges, I discussed the core functionality of layer 2 switches. In this blog, I hit upon the Spanning Tree Protocol (STP) used on layer 2 switches to prevent loops. As mentioned before, … Continue reading →

Posted in Cisco, Labs, Networking, Protocols, Technology | Tagged Blocking, BPDUs, bridge ID, Bridge Protocol Data Units, broadcast storm, change root bridge, Cisco, Cisco 3560, designated port, device priority, Disabled, Forwarding, layer 2, layer 2 loop, Learning, Listening, loop, MAC address, prevent layer 2 loop, prevent loop, redundancy, root bridge, root port, Spanning Tree Protocol, STP | 1 Comment

The Rise of the Hybrid Cloud

Posted on January 15, 2012 by Humair

As many organizations move their corporate services to private clouds to cut costs, enable rapid provisioning of resources, enable advanced monitoring, and increase up-time, I believe we will see a continuous uptake of solutions which tie private cloud services and … Continue reading →

Posted in Business, Technology, Technology, Virtualization and Cloud Computing | Tagged Amazon S3, Amazon Simple Storage Service, American cloud companie, avoid US cloud, avoid US-based cloud, cloud, controversial Patriot Act, hybrid cloud, Jon Stokes, non-US cloud provider, Patriot Act, PATRIOT Act Gives Foreigners Good Reason to Avoid US Cloud, private cloud, public cloud, unconstitutional Patriot Act, United States Patriot Act, VPN | Leave a comment

How to Transfer Your Putty Settings Between PCs Running Windows

Posted on January 8, 2012 by Humair

I can’t tell you how many times I’ve had people ask me how they can export their Putty settings. For those of you who have been completely in the dark for the last decade, Putty is a Telnet and SSH … Continue reading →

Posted in Applications, Hacks, Networking, Operating Systems, Technology, Tips & Tricks, Windows, Windows 7, Windows Server 2008 R2 | Tagged export putty, export putty settings, export windows putty, export windows putty settings, hack, putty, putty hack, putty hack to export settings, putty windows registry hack, regedit, registry hack, Simon Tathamm, ssh client, telnet client, transfer putty settings, transfer putty settings between computers, transfer putty settings between pcs, windows, Windows 7, windows 7 registry hack, windows regedit, windows registry, windows registry hack | 8 Comments

Cisco – Filtering Unwanted Packets with Standard Access Lists

Posted on January 7, 2012 by Humair

Access lists (ACLs) are basically statements that packets are compared against for the purpose of taking some action if a match occurs. After an access list is created, it can be applied to inbound or outbound traffic; in some cases … Continue reading →

Posted in Cisco, Labs, Networking | Tagged access list, access lists, acess-lists, ACL, ACLs, block host, block ip address, block packet, block traffic, Cisco, Cisco 2611, Cisco 2611 router, deny host, deny ip address, deny packet, deny traffic, extended access list, filter, filter host, filter ip address, filter packet, filter traffic, named access list, router, standard access list, standard access-lists | 1 Comment

Perl – Changing the Input Line Separator and Using the “chomp” Function

Posted on January 6, 2012 by Humair

In this blog I demonstrate how you can change the input line separator in Perl and use Perl’s “chomp” function. Note, the input line separator is operating system dependent; see the following prior blog of mine where I discuss this … Continue reading →

Posted in Perl, Programming Languages, Technology | Tagged $/, $/ system variable, change the input line separator, chomp, chomp function, input line separator, input line separator system variable, input line separator variable, perl, perl input line separator system variable, perl input line separator variable, remove newline, remove newline character | Leave a comment

Perl – Uppercase to Lowercase Conversion via the Translation Operator

Posted on January 4, 2012 by Humair

Perl’s translation operator provides a way to substitute one group of characters for another. In the below script I demonstrate how easy it is to use the translation operator to convert standard input from the command prompt from uppercase letters … Continue reading →

Posted in Perl, Programming Languages, Technology | Tagged code, conversion, convert, lc, lc function, perl, perl code, substitute, substitute group of characters, substitution, translation, translation operator, uppercase to lowercase | Leave a comment

OSPF Explained and Useful Troubleshooting Commands

Posted on January 4, 2012 by Humair

Open Shortest Path First (OSPF) is an open standard link-state routing protocol that supports multiple equal-cost routes to the same destination (four by default). OSPF constructs a shortest path tree and then updates the routing table with the best paths. … Continue reading →

Posted in Cisco, Labs, Networking, Protocols, Technology, Troubleshooting | Tagged ABRs, adjacency, area 0, Area Border Routers, AS, ASBR, Autonomous System, Autonomous System Border Router, backbone area, Backup Designated Router, BDR, Cisco, Cisco 2126XM, Cisco 2126XM router, Cisco IOS, cisco router, cost, Designated Router, Hello packets, Link State Advertisement, LSA, neighbor, Neighbors, Open Shortest Path First, OSPF, OSPF Adjacencies, OSPF area, OSPF Backup Designated Router, OSPF BDR, ospf cost, ospf database, OSPF Designated Router, OSPF Hello Packets, ospf neighbor, OSPF Neighbors, OSPF process, OSPF Router ID, ospf troubleshooting, router, Router ID, Shortest Path First, shortest path tree, SPF | 3 Comments

Perl – Using Pattern-sequence Memory with Regular Expressions

Posted on December 29, 2011 by Humair

Pattern-sequence memory is very useful when you want to match the same character in several places but don’t care which character you match as long as all occurrences are the same character. For example, the below code matches the date … Continue reading →

Posted in Perl, Programming Languages, Technology | Tagged pattern memory, pattern-sequence, pattern-sequence memory, Pattern-sequence Memory with Regular Expressions, perl, perl regular expressions, regex, regular expressions, sequence memory, Using Pattern-sequence Memory with Regular Expressions | Leave a comment