ccna newbie

mark_s0

Hi all,

I've been reading this forum for quite a while now although I haven't really posted much before, but I'm hoping to get some help with my studies whilst assisting other with theirs.

I've just started studying for my CCNA in an attempt to further my career in networking and security.

My study aids are CBT nuggets and Todd Lammle's 6th Edition and until I can afford proper equipment, I'm using Packet Tracer to learn IOS commands.

This is kind of a "hello" post but I do have a question...

I've been watching Jeremy on CBT nuggets talking about access lists so I figured I'd try it out. My current situation is as follows:

PC0 - > - Router0

---

Router1 - > - PC1

IP addresses are:

PC0 - 192.168.1.2
Router0 fa0/0 - 192.168.1.1
Router0 eth1/0 - 192.168.3.1
Router1 eth1/0 - 192.168.3.2
Router1 fa0/0 - 192.168.2.1
PC1 - 192.168.2.2

I think I have an basic understanding on how access lists work i.e setting the correct rule for the correct direction and interface etc.

My problem is I don't seem to be able to ping from one PC0 to the PC1. I've tried different permit rules but I still seem to be failing. My only thought is maybe the routing isn't set up properly on each router as I can ping 192.168.3.1 but not 192.168.3.2.
Routing isn't something I've studied yet so this is more of an educated guess than anything else.

Has anyone got any pointers for me?
It seems to have fried my brain so please excuse if I've missed anything out.

Many thanks and I'm looking forward to studying with you all!

Mark

bigheadx

Configs please?

If your able to ping a side of one router, but not the other side, is it up?

For example, can the other PC ping the side your first pc cant ping?

mark_s0

bigheadx, thanks for getting back to me.

Configs attached. If I'm running a ping from 192.168.1.2, I get successful replies from both 192.168.1.1 and 192.168.3.1 interfaces but not 192.168.3.2 or 192.168.2.0 (the other side). And the "destination host unreachable" I get comes from 192.168.1.1.

It's the same vice versa, on PC1 i can't ping 192.168.3.1 or 192.168.1.0.

All needed interfaces are definitely up.

Maybe i've misunderstood the one access-list per protocol, per interface, per direction part

Thanks for your help.

Mark

notgoing2fail

Welcome aboard Mark. I looked at your configs but let's slow it down a bit first.

Forget about ACLS's at the moment. In fact, remove them all from both routers. You need to start first with a couple of things.


1) Cabling. Do you have the right cable? Are you using crossover?

2) Without ACL's involved, you can then check to see if you can ping across both ways from both PC's.


Once you can establish BASIC connectivity, you can then get a little fancy with ACL's....

mark_s0

Hi notgoing2fail,

I've started from scratch, no ACL's or anything.

I've connected pc to router using crossover and from router to router using crossover.

Unfortunately I'm not able to ping the 192.168.2.0 network nor the 192.168.3.2 interface from 192.168.1.0 network. I'm missing something but I can't see what.
Obviously i'm not after handholding or the answers (I handhold too many people at work so I know how annoying it is ), but some direction of where I should think about would be nice Maybe I should read more of the theory and come back to it?

thanks once again for your help,

Mark

notgoing2fail

mark_s0 wrote: »

Hi notgoing2fail,

I've started from scratch, no ACL's or anything.

I've connected pc to router using crossover and from router to router using crossover.

Unfortunately I'm not able to ping the 192.168.2.0 network nor the 192.168.3.2 interface from 192.168.1.0 network. I'm missing something but I can't see what.
Obviously i'm not after handholding or the answers (I handhold too many people at work so I know how annoying it is ), but some direction of where I should think about would be nice Maybe I should read more of the theory and come back to it?

thanks once again for your help,

Mark

Hmm...well I'm having a brain burp right now but shouldn't the PC to Router be using a straight-through cable?

router to router = crossover
router to switch = straight
router to PC = straight


I could be wrong about the router to PC but I think it should be straight...

notgoing2fail

You don't have a default gateway on the routers so add this to each router:



router0 add this line:


ip route 0.0.0.0 0.0.0.0 192.168.3.2



And for router1 add this line:


ip route 0.0.0.0 0.0.0.0 192.168.3.1

alan2308

notgoing2fail wrote: »

Hmm...well I'm having a brain burp right now but shouldn't the PC to Router be using a straight-through cable?

router to router = crossover
router to switch = straight
router to PC = straight


I could be wrong about the router to PC but I think it should be straight...

router to pc should be crossover

alan2308

notgoing2fail wrote: »

You don't have a default gateway on the routers so add this to each router:



router0 add this line:


ip route 0.0.0.0 0.0.0.0 192.168.3.2



And for router1 add this line:


ip route 0.0.0.0 0.0.0.0 192.168.3.1

Thats a default route, not a default gateway.

notgoing2fail

alan2308 wrote: »

router to pc should be crossover

Ok thanks, brain burp!

alan2308 wrote: »

Thats a default route, not a default gateway.

Another brain burp....

mark_s0

ah you guys are great! I now have full connectivity across all 3 networks! Default route did it. Now I can dive into ACL's, although I'm going to go back to cbt's to make sure I've understood everything ok.

thank you very much for all your help, much appreciated! A great start to getting involved in this forum.

I can tell this forum is going to be really valuable during my studies.

Enjoy the rest of your weekend!

Mark

alan2308

mark_s0 wrote: »

ah you guys are great! I now have full connectivity across all 3 networks! Default route did it. Now I can dive into ACL's, although I'm going to go back to cbt's to make sure I've understood everything ok.

thank you very much for all your help, much appreciated! A great start to getting involved in this forum.

I can tell this forum is going to be really valuable during my studies.

Enjoy the rest of your weekend!

Mark

The one thing that seems to get people early on (myself included) is forgetting that the device that you're trying to ping has to have a route back to the device that sent the ping. I spent countless hours trying to figure out why PC0 couldn't reach PC1 in a situation like yours when in fact PC0 could reach PC1 just fine.

But most importantly, welcome aboard!

notgoing2fail

alan2308 wrote: »

The one thing that seems to get people early on (myself included) is forgetting that the device that you're trying to ping has to have a route back to the device that sent the ping. I spent countless hours trying to figure out why PC0 couldn't reach PC1 in a situation like yours when in fact PC0 could reach PC1 just fine.

But most importantly, welcome aboard!

Agreed, when I read his issue, I knew right away what the problem probably was....

Too bad I got my terminology wrong...LOL!!!

alan2308

notgoing2fail wrote: »

Agreed, when I read his issue, I knew right away what the problem probably was....

Too bad I got my terminology wrong...LOL!!!

It happens to the best of us.

Deathgomper

alan2308 wrote: »

I spent countless hours trying to figure out why PC0 couldn't reach PC1 in a situation like yours when in fact PC0 could reach PC1 just fine.

That brings back memories.

Note: That on my 2505 routers running 10baseT ethernet you need a strait through cable vs my 2611xm with fastethernet port which uses a crossover cable to connect to pc.

Which brings me back to the quote.