brick walled with ACLs and subnetting

pinkiaiii

So,hi all
this forums seems very friendly and handy place to gather information and learn.

im almost 3 months now into ccna,and and have 3 major hickups following me,now lecturers decided to skip many chapters from netacad to do ACLs,and this journey has nothing been just smashing wall after wall with each chapter.

So first input im looking can anyone suggest proper video or link that explains wildcards, i get the simple idea of 255-let it all or deny, but numbers as 0.0.0.0 or 0.0.0.1 to allow even or odd networks drive me crazy not to mention ways to put wildcard mask into single line to support different range of IPs needed.

next issue i still suck majorly on subneting i get class c and a bit of b when counting backwards for hosts and networks,but ive no clue how could say address ending in 255 still be valid address,or the way bits jump from one octet to another.

and last its ipv6 ive no clue why someone bothered to invent something that cruel,but for sake of me i only know basics and wouldnt be able to apply it or yet to distinguish it from global,link local or the way its subneted.

I guess its a lot to tell and ask but feel like im slowly drowning in this course-ps doing part time,so most stuff has to be learned doing free time,which i give between 2-6 hours on most days,and yet i can do full day come back to same topic theory and be blank on it.

Just venting as looking for help if anyone were at some point in similar issues as still have around 5 months to prepare for exam this being start of semester 2 doesn't seem like a good one.

All that said when started semester 1 i felt almost the same now it seems like walk in the park,but also thinking that at some point all that info will have to come together scares the crap out of me.

NVLady

For me, the trick to subnetting was the Magic Box. You can learn about it from this doc https://learningnetwork.cisco.com/servlet/JiveServlet/downloadBody/2413-102-1-6606/CCNA%20Prep-%20IP%20Subnetting%20from%20Networkers.pdf. I basically memorized the box and block sizes.

One you get it down, I would recommend spending some time at subnettingquestions.com - Free Subnetting Questions and Answers Randomly Generated Online. When you take the test, you won't have a lot of time to spend subnetting. Prior to taking my CCNA Exam, I could answer those questions in my head.

Good luck!

toasterboy1

Learned subnetting the hard way first but really liked this post: http://www.techexams.net/forums/ccna-ccent/38772-subnetting-made-easy.html
Just subtraction and powers of 2 to find your block size. I will have to find the micro nugget for wildcards but pretty much the opposite of you network submask. So 255.255.255.0 would be 0.0.0.255, 255.255.192.0 would be 0.0.63.255. Do not get me started on ipv6. I understand the reason for needing it but cannot wrap my head around HEX and 128bits. The last 64 are the actual node and the first 64 become the network but how the network gets figured out is beyond me. Plus your device can have multiple addresses. *head explodes*

pinkiaiii

Amen brother for your post about ipv6 -dont know why someone thought having 128 bit long address that humanly is impossible to remember and typing it out alone is just hell-thus get idea that we need more addresses,but with that said no wonder no one wants to move away from ipv4 bring that over 20y passed and its still taboo, rant over-as said this can be talked for ever

But actually just by saying that 255.255.192.0 you shed some light onto me with that example-even thou i know it only applies to single ip.

That said i have latest ccna lammle book,and some r&s books,but even thou i managed to learn most basic commands and set ups,the share amount of information and new commands that add up make me crazy,as tried to set up PT lab the other day and took me 30mins to remember how to set up static routes on routers to do some ACLs.

And funny thing is aside all this that college that im doing course in,all lecturers are so busy and either presume we know the stuff when they go over it in 30mins time or say oh well ive passed my ccna 3-12 years ago and basically these questions might pop up in your exams - thus i get this impression be it professional but someone who works already they dont bother with ccna specifics or basics once they did it they just find information on stuff that they need to remember,as they did it years ago and actually themselves are riddled the way new courses are set up,the order of topics and chapters that are important are pushed way back and stuff that were just a line or two about single topic ,now we have pages written about it.

Segovia

That is why DNS is a huge deal with ipv6..

OP, I feel your pain. But I think I know part of your problem. Are you using Netacad as your primary learning material? If so, chuck it in the trash ASAP. Well, still work through it if you have to for school lol. But the reading material for Netacad is so dry and technical, almost to a point where Cisco wants you to be confused. Try other methods like videos or pick up a book or two. Once you learn these topics from a good teacher they will start to stick. Trust me

Good luck on your CCNA journey!

fmitawaps

I've never had much trouble with SOME parts of subnetting. As long as I have the subnet chart, any question that asks something like "what is the first usable host in 172.145.126.73 /24?" ( the answer is 172.145.126.1), I just look up the numbers and think it out, I never got into counting bits and all that sort of thing. For a question like this, I know from sheer repetition that a /24 mask has 256 addresses, and 126.1 is the first available host. No counting bits involved.

But I never did well at questions that ask how many subnets and hosts per subnet can be gotten from a certain address and subnet mask. I will just have to hope there aren't many of those questions on my CCENT exam. If I ever have to figure it out on a job, that's what Google is for.

Segovia

There are a lot of subnetting questions on the ICND1, and they can be really confusing. As a matter of fact, I doubt you will get a question about a /24 network. And while some situations call for using a subnet calculator, I would want to know why and how the addressing scheme was calculated before randomly applying it to a new network and hoping for the best.

I would suggest approaching subnetting from various teaching sources

pinkiaiii

yes netacad is main platform we use for learning and its nothing like crashing into wall within each chapter.
If i knew stuff 6 months back what i know now,id just get PT and onto danscourses to go properly over subneting and ipv6 just to get a proper head start.as most stuff is basic as in commands for semester 1,but they chuck in subneting and ipv6 in there as well and let you week to get topics straight into your head when actually if someone is new to that id say maybe month is more realistic to get it right before one could easily spill out answer to any related question.but in netacad its week on your own time and then next chapter to move on.

edit:posted before so could be double post if so admins please delete previous post.thank you.

toasterboy1

Did you read thought the technotes here: TechExams.Net - CCNA TechNotes: IP Access Lists Explains wildcard masks.

Ltat42a

This guy has a 13 video series on ACL's, everything done on live equipment -
https://www.youtube.com/user/ccie12933

pinkiaiii

toasterboy1,Ltat42a thank you for links above.

stlsmoore

IPv6 gets easier to remember and learn over time, just like anything it's all about repetition learning. Inherently it is a lot more scalable and at least in theory should be a lot less complex to design than IPv4.

Part of IPv6's protocol design is to eliminate the need for NAT and to allow for automatic addressing without the need for a DHCPv6 server (not sure how much this would be used). IPv6 is also a lot more efficient than IPv4. It has a fixed IP header size (40 bytes) instead of the variable length IPv4 headers, along with not supporting broadcasting at all.

pinkiaiii

stlsmoore-thanks for input,issue is when you grow up 20years using ipv4 them 4 octects,easily stick in your head after such long time,and when you see something like 192.168 its straight forward as opposed to seeing 2001:0:9d38:90d7:2803:1c8:a69b:6662

thus if one was to tell me their ipv4 chances are id recall that up to last digit with no issues,with ipv6 chances are id propably mess up some letter and end up getting it wrong not to mention remembering the damn thing.

Anyway been looking at few youtube videos and cant seem to find one that explain it the way that it would stick,plenty of vids on comparing the two and giving couple examples but thats about it.

I know the reason its needed and all,even my isp has me on dual stack,since they are basically out of giving ipv4 addresses.
But besides huge data centers and global corporations,id been what 20 years now or so,and seen it mentioned in videos 4-6 years people being told ipv6 is the future,but in many cases that future is yet to come.

Anyway given its christmas holidays and off for the month my head is spinning as so much to catch on to subneting is still major issue for me past class C,got my head around vlans for better part,not ACLs do get the point in using them and say where one would put one acl and so on,but then there is a lot more commands that i seem just to forget when combining all what ive learnt so far,vlans acls,subnets,hopefully mood will lift and will get cracking at those topics soon.

Only other question as asked in class and got sort of unknown answer-when doing ccna exam are you allowed to use questions marks as to see what other options can be used,as was told it varies year from year,since no doubt there will be few labs and most likely acl and whatever else they have coming,thus knowing ccna tricks now,wouldn't be surprised to see that one cant use Context help.