General questions regarding CCNA topics

Hello!

Just a few general Qs

1.) How do you check what ports are set as trunk ports on a switch without going through each interface?

ie.

show trunk fa0/1
show trunk fa0/2
etc

2.) Can extended access lists be written without adding the protocol at the end? or adding any instead of a number or protocol letter

ie.

access-lists 101 permit tcp 10.0.0.4 0.0.0.3 10.0.0.12 0.0.0.3 eq any

can I leave the eq any part blank? or use eq any to allow any TCP protocols through?

Thanks

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Comments

bbarrick

Will the show interfaces command help on 1?

show vlan id num?

Just read this in the book so I'm not 100 percent sure, just trying to learn at the same time.

shabeerm

Sounds Good wrote: »

Hello!

Just a few general Qs

1.) How do you check what ports are set as trunk ports on a switch without going through each interface?

ie.

show trunk fa0/1
show trunk fa0/2
etc

2.) Can extended access lists be written without adding the protocol at the end? or adding any instead of a number or protocol letter

ie.

access-lists 101 permit tcp 10.0.0.4 0.0.0.3 10.0.0.12 0.0.0.3 eq any

can I leave the eq any part blank? or use eq any to allow any TCP protocols through?

Thanks

1) You can check trunk ports by below commands

show interface trunk
show interface fa 0/24 trunk

2)You can leave eq part blank. that's optional only.You can block internet either by using www or port number 80 after eq .
You can use protocols like IP or TCP or ICMP with extended access-lists

Hope this helps

Sounds Good

shabeerm wrote: »

1) You can check trunk ports by below commands

show interface trunk
show interface fa 0/24 trunk

2)You can leave eq part blank. that's optional only.You can block internet either by using www or port number 80 after eq .
You can use protocols like IP or TCP or ICMP with extended access-lists

Hope this helps

1.) So if I type in "show interface trunk" , that will tell me which ports are set to trunk mode correct?

2.) If I just leave an access-list as the following,

access-lists 101 permit tcp 10.0.0.4 0.0.0.3 10.0.0.12 0.0.0.3

this would work to permit all tcp access for 10.0.0.4 to 10.0.0.7 correct?

Thanks

mella060

Sounds Good wrote: »

1.) So if I type in "show interface trunk" , that will tell me which ports are set to trunk mode correct?

2.) If I just leave an access-list as the following,

access-lists 101 permit tcp 10.0.0.4 0.0.0.3 10.0.0.12 0.0.0.3

this would work to permit all tcp access for 10.0.0.4 to 10.0.0.7 correct?

Thanks

1.) Correct. Yes the show interfaces trunk command will list all trunks and the associated ports running on a switch.

2.) Correct

Sounds Good

Another question

Say I have 3 routers,

Router 1

Router 2

Router 3
| ___________________|__________________|
| ___________________|__________________|
| ___________________|__________________|
host 1 _____________host 2_____________host 3

Say I ping form host 1 to host 3, but router 3 is down. What is the order how how the message "destination unreachable" will come to be?

Will router 2 send "destination unreachable" to Router 1?

Thanks and please elaborate

bbarrick

Sounds Good wrote: »

Another question

Say I have 3 routers,

Router 1
Router 2
Router 3
| ___________________|__________________|
| ___________________|__________________|
| ___________________|__________________|
host 1 _____________host 2_____________host 3

Say I ping form host 1 to host 3, but router 3 is down. What is the order how how the message "destination unreachable" will come to be?

Will router 2 send "destination unreachable" to Router 1?

Thanks and please elaborate

I'm studying for the 100-101 so I was watching for an answer to your question. Just my guess but wouldn't R1 forward a packet to R2, R2 would check the destination and see that the interface for R3 is in a notconnect status, copy the source address and create a frame to send back containing the error code for "destination unreachable" to R1 and back to host1?

JeanM

Are you currently studying for CCNA or already passed it?

Sounds Good

JeanM wrote: »

Are you currently studying for CCNA or already passed it?

I passed it today =]

Ltat42a

shabeerm wrote: »

1) You can check trunk ports by below commands

show interface trunk
show interface fa 0/24 trunk

You can also use show vlan. This command will show you all ports assigned to vlans, it doesn't show what ports are assigned as a trunk port. If you don't see Fa0/11 with this command, you can verify it with show interface trunk.

shabeerm

Sounds Good wrote: »

Another question

Say I have 3 routers,

Router 1
Router 2
Router 3
| ___________________|__________________|
| ___________________|__________________|
| ___________________|__________________|
host 1 _____________host 2_____________host 3

Say I ping form host 1 to host 3, but router 3 is down. What is the order how how the message "destination unreachable" will come to be?

Will router 2 send "destination unreachable" to Router 1?

Thanks and please elaborate

If the interface that host 3 connected to router is down,then Router 3 send destination unreachable message and also uses ICMP to inform host 1 that host 3 is down

If the other interface that router 3 connected to router 2 is down,then i think router 2 will send destination unreachable message