CCIE Candidate

These are facts I did not know (or was unsure of) that I picked up while going through the CD-ROM testing engine for chapters 1-6. Take this with a grain of salt, as these testing engines are notorious for technical errors.

The OECG book came with a CD-ROM that’s got a Boson test engine on it.  You can test on specific book categories.  So, starting tomorrow night, that’s what I’m going to.  I’m going to work on sample questions from the test engine, and brush up on the weak spots.  I’ll note down in a post [...]

passive mode FTP - an FTP mode where the server dynamically allocates a port and the client opens a socket to that port from a port he dynamically allocated.
active mode FTP - an FTP mode where the client dynamically allocates a port, and the server opens a socket to that port from his source port [...]

On to some of the common applications that ride on TCP and UDP. The author touches on FTP (active and passive modes), SSL/HTTPS/TLS just briefly, and closes with SNMP. Accompanied by Beethoven’s Rondo from Piano Concerto No. 2, I soldier on. Quickly, I might add, as the morning will find me at [...]

Just before we get into routing in chapter 7, we’re going to review a few more “odds and ends”. In this chapter, we review the basics about the most commonly used transport protocols that ride on IP: TCP & UDP. In addition, we review FTP & SNMP (which I’ll hit in the [...]

While I’m focusing on theory right now so that I can get through the written exam, I’m also thinking about the coming lab. I’m looking forward to the lab prep work, because I love hacking on routers. It’s what I do for a living, and it will be nice to get to the [...]

HSRP - hot standby routing protocol. Cisco proprietary. Features a virtual IP and MAC 0000.0C07.ACxx (where xx is the group number) that float amongst members of the group, held by the active HSRP router. For redundancy, not inherently load-balancing.
VRRP - virtual router redundancy protocol, RFC 3768. Very similar [...]

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 & [...]

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.  Somewhat [...]

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 [...]

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, [...]

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 [...]