--- nanog@nanog.org wrote: From: Grant Taylor via NANOG <nanog@nanog.org> You can safely say that 72.234.7.0/24 is a Class C /sized/ network. -------------------------------------- But most don't say that. They just say it's a Class C, which it most assuredly is not. I heckle them until they can give the correct answer: leading bits are 110 or it's not a Class C subnet. scott
On 12/18/18 2:58 PM, Scott Weeks wrote:
You can safely say that 72.234.7.0/24 is a Class C/sized/ network. --------------------------------------
But most don't say that. They just say it's a Class C, which it most assuredly is not. I heckle them until they can give the correct answer: leading bits are 110 or it's not a Class C subnet.
scott
This is a favorite interview type question of mine, but I won't disqualify a candidate if they can't come up with the reason. It's more of a probe for historical domain knowledge (one of many I'll slip in). -- Brandon Martin
On Dec 18, 2018, at 5:43 PM, Brandon Martin <lists.nanog@monmotha.net> wrote:
On 12/18/18 2:58 PM, Scott Weeks wrote:
You can safely say that 72.234.7.0/24 is a Class C/sized/ network. -------------------------------------- But most don't say that. They just say it's a Class C, which it most assuredly is not. I heckle them until they can give the correct answer: leading bits are 110 or it's not a Class C subnet. scott
I am certain that I read the RFC years ago, but I can’t remember it. Which RFC?
This is a favorite interview type question of mine, but I won't disqualify a candidate if they can't come up with the reason. It's more of a probe for historical domain knowledge (one of many I'll slip in). -- Brandon Martin
On 12/18/18 5:52 PM, James R Cutler wrote:
I am certain that I read the RFC years ago, but I can’t remember it. Which RFC?
RFC796 defines the address formats for classes A, B, and C. A starts with a 0 bit, B starts with 10, and C starts with 110 according to said RFC. -- Brandon Martin
On Tuesday, 18 December, 2018 22:43, "Brandon Martin" <lists.nanog@monmotha.net> said:
This is a favorite interview type question of mine, but I won't disqualify a candidate if they can't come up with the reason. It's more of a probe for historical domain knowledge (one of many I'll slip in).
It's an interesting flag at interview for me, if it comes up, but I wouldn't normally talk about it unless the candidate does first. -If they don't know or mention classful networking at all, they're new (relatively, I'm old), and that's fine. -If they can get it right, they're either a long-timer or have done some network history. -If they try to use it, and get it wrong, or can't properly explain it, there's a warning that they've been cramming network skills from some old and/or low-quality sources. I'd start probing for other warning signs like /24s on point-to-point serial links, RIPv1, and the like. Regards, Tim.
participants (4)
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Brandon Martin
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James R Cutler
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Scott Weeks
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tim@pelican.org