Common operational misconceptions

Thu Feb 16 06:20:37 UTC 2012

Some recent questions from interview and lab sessions I took.

- I've allowed vlan X on trunk but still its not working? why do I have to
create it on every switch?
- any-any rules on firewall with AV enabled is better.
- ACL inboud/outbout misconcept. Always end up cutting the rope.
- BGP is for ISPs only.
- MPLS is for security and is fast.

Regards,

Aftab A. Siddiqui

On Thu, Feb 16, 2012 at 11:00 AM, Kenneth M. Chipps Ph.D. <chipps at chipps.com
> wrote:

> "ISIS is used in organizations other than ISPs" Any examples you can share
> of some other than ISPs?
>
> -----Original Message-----
> From: Joel jaeggli [mailto:joelja at bogus.com]
> Sent: Wednesday, February 15, 2012 11:58 PM
> To: Kenneth M. Chipps Ph.D.
> Cc: nanog at nanog.org
> Subject: Re: Common operational misconceptions
>
> On 2/15/12 21:04 , Kenneth M. Chipps Ph.D. wrote:
> > How widespread would you say the use of IS-IS is?
> >
> > Even more as to which routing protocols are used, not just in ISPs,
> > what percent would you give to the various ones. In other words X
> > percent of organizations use OSPS, Y percent use EIGRP, and so on.
>
> Using EIGRP implies your routed IGP dependent infrastructure is a
> monoculture. That's probably infeasible without compromise even if you are
> largely a Cisco shop.
>
> ISIS is used in organizations other than ISPs.
>
> > -----Original Message-----
> > From: Antti Ristimäki [mailto:antti.ristimaki at gmx.com]
> > Sent: Wednesday, February 15, 2012 10:47 PM
> > To: John Kristoff
> > Cc: nanog at nanog.org
> > Subject: Re: Common operational misconceptions
> >
> > "IS-IS is a legacy protocol that nobody uses"
> >
> >
> > 15.02.2012 22:47, John Kristoff kirjoitti:
> >> Hi friends,
> >>
> >> As some of you may know, I occasionally teach networking to college
> >> students and I frequently encounter misconceptions about some aspect
> >> of networking that can take a fair amount of effort to correct.
> >>
> >> For instance, a topic that has come up on this list before is how the
> >> inappropriate use of classful terminology is rampant among students,
> >> books and often other teachers.  Furthermore, the terminology isn't
> >> even always used correctly in the original context of classful
> addressing.
> >>
> >> I have a handful of common misconceptions that I'd put on a top 10
> >> list, but I'd like to solicit from this community what it considers
> >> to be the most annoying and common operational misconceptions future
> >> operators often come at you with.
> >>
> >> I'd prefer replies off-list and can summarize back to the list if
> >> there is interest.
> >>
> >> John
> >>
> >
> >
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