Ethan Banks

We’re getting ready to wrap up OECG chapter 5 with a discussion of NTP, or network time protocol. That which keeps your router’s date and time synchronized with some master time server. Having everyone on your network keep time synched to a common source is a critical function to have, for logging & event correlation, […]

I am not a machine.  I can’t devote my brain to one stream of consciousness for more than about two or three hours without a major break.  And that’s if everything is going swimmingly well.  Here’s what I do to keep the fire burning: Classical music.  I listen to music obsessively.  Can’t stop myself, really.  […]

Moving on from ICMP & getting an address, we now move on to how to move out of our local subnet. For starters then, let’s discuss some protocols that were created because most devices on a network are statically configured with a single gateway. HSRP – Hot Standby Router Protocol, Cisco proprietary.

After ICMP, we get into some of the protocols used so that hosts can find out about each other and about themselves. ARP – address resolution protocol, RFC 826. ARP is how a host who knows the IP address of his destination finds out the MAC so that he can properly put a frame on […]

I’m going to start breaking these up a bit more, as generally the chapters are broken up into major groups, and doing 1 or 2 part posts for each chapter is just way too much information in a single post. Without further ado, the glories of Official Exam Certification Guide, Chapter 5. ICMP – internet […]

subnet – some portion of a larger network. Subnets can be classful or classless. prefix – the portion of a classless IP network that comes before the host. Often noted with / notation, where the number following the slash represents the number of bits that makes up the subnet.

I’ve spent a few hours on the Cisco NetPro forums, and on the GroupStudy Cisco mailing list. For me, they aren’t helping. My level of knowledge is often somewhere above most of the people asking the questions, but usually somewhere below most of the people answering the questions. A lot of times, I’m pretty sure […]

And now on to IPv6, which was a pretty brief part of the chapter really, but I wanted to devote a page all to itself, since the last post was so long. IPv6 was designed to fix the Internet address space problem permanently. And amazingly enough, they managed to complicate things more than a lot. […]