2 question of P4sure v.295 not clear....Help me please

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I haven't understand 2 questions in P4sure v.295....

Exam 5, question 38 and 55....

I don't know how to attack the problems....


Can someone explain me why i can relesolve these questions????



Thks

Dude, post the screen shots.




Excuse me... how can upload an image saved in my pc????


1. Alt-PrtScn of p4s question
2. Paste into mspaint or similar and save
3. Upload the image to an image hosting website
4. Once uploaded you get a URL and post that between URL tags in your message.



Question 55:

Question 38:

The correct answers are selected....

hello, did you performed searching for question 55, it has been answered anyway correct option is C, all other options are wrong

regarding other question i dont think C is correct becoz when we are natting we dont need Routing between R4 and R7
Option B is Correct, you need to remove this static NAT entry that is using Translation to and from R4 to R6 and replace with the dynamic NAT which is shown as a Pool of range of Ip addresses.




I have marked the answers as are in P4S.....

Regarding question 55,
if the RID of RouterA is 221.130.149.10, as we can see from show ip protocols, why the designated Router ID is 208.149.23.194, that is inferior????maybe that the priority of Router A is inferior of the priority of the Designated router, but where i can see this????

Regarding question 48:
I don't know what type of NAT is done becouse i have seen that:

static nat: ip nat inside source static ...
dynamic nat: ip nat inside list "acl-number"pool "POOL" [overload]

So i think that in example the nat is missconfigured so we have to configure it in the correct manner.... but is necessary define an access-list .... or i wrong?????



Thanks for any help

Any suggestion???? Please help me...




For q55 you ask where can you see this. You can't but logic dictates that that can be the only reason why the router in the output is not the DR. As you pointed out it has a higher RID so they only thing that precedes that in the DR election process is highest configured priority so it has to be that.

For q48 there is static NAT and dynamic NAT occurring, the former to R5, the latter to R7. NAT is configured correctly so it must be C.

no comment about the question 55 as it has been answered in a good way above
regarding the other question , question 48 if you notice the dynamic NAT is missing a ACL so its not used even ( correct me if im wrong ) , so what is used only is the static ip , the ip 10.10.10.4 is the same 172.16.6.14 ( from the static nat ) and it can ping by default any ip in the range 172.16.6.0/24 as declared in the pic so wats left ? the ip of router 7 !
nothing to NAT for it ...etc so we need a static NAT to that as well or A STATIC ROUTE !
so answer C is correct !




q55 ---> OK

q48 ---> ????

you say that for R5 is occurring static NAT (ip nat inside source static 10.10.10.4 172.16.6.14) where 10.10.10.4 is the ip of R4 fa0/1, but the ip of R5 fa0/0 is 172.16.6.5 (from the figure), so i think you suspect that the figure is wrong (isn't it ????????)

than for R7 is occurring dynamic NAT (ip nat inside pool test)
For this configuration i have 2 question:
1) if an ACL isn't applied it is valid for any source ip ???
2) imagine that R4 is pinging R7: R4# ping 172.16.11.7, the packet arrives at R6 (i supposed that in R4 i have ip default-gateway 10.10.10.6), when the packet arrived to R6 NAT occurr:
"ip nat inside pool test", the packet goes on s0/0 with souce ip 172.16.11.70 or 172.16.11.72 and destination 172.16.11.7, so the echo request arrived on R7. R7 in the echo replay put is ip as source and 172.16.11.70 or 172.16.11.72 as destination and the packet return on R6, where in the ip nat translation table there is the association inside local/inside global, and the echo replay goes to R4..... all work fine for me..... where i wrong?????


Thanks a lot




now i have read your replay....

I supposed you are right... if there isn't an ACL the dynamic nat is never applied and not as i have written (always).....

So now is a litter more clear but not all....

You say that for resolve this problem we can use a STATIC ROUTE in R7 back to R4.... ok clear....

but how can R4 forward a packet to R7 if there aren' t routing protocol???

There is a static default route to R6 as i have supposed????


very tanks to all

you say that for R5 is occurring static NAT (ip nat inside source static 10.10.10.4 172.16.6.14) where 10.10.10.4 is the ip of R4 fa0/1, but the ip of R5 fa0/0 is 172.16.6.5 (from the figure), so i think you suspect that the figure is wrong (isn't it ????????)

no , i meant that you can assume that Fa0/1 on R4 is having the IP 172.16.6.14 so by default it can ping any ip in the range 172.16.6.0/24 ! coz that it can ping anything related to router 5 ! or even router 6 interface if u want

than for R7 is occurring dynamic NAT (ip nat inside pool test)
the nat is on router 6 not router 7 !

For this configuration i have 2 question:
1) if an ACL isn't applied it is valid for any source ip ???

NO , that means the NAT command isnt completed so it wont function ( the dynamic nat only ! ) and if you wana assume that it will work with a hidden ACL , it will contain an implicit deny if u remember the rules of ACL so everything will be blocked that is if you have a hidden ACL , so just assume the dynamic nat isnt there even ! we will assume in thsi example that the dynamic NAT is working !

2) imagine that R4 is pinging R7: R4# ping 172.16.11.7, the packet arrives at R6 (i supposed that in R4 i have ip default-gateway 10.10.10.6), when the packet arrived to R6 NAT occurr:
"ip nat inside pool test", the packet goes on s0/0 with souce ip 172.16.11.70 or 172.16.11.72 and destination 172.16.11.7, so the echo request arrived on R7. R7 in the echo replay put is ip as source and 172.16.11.70 or 172.16.11.72 as destination and the packet return on R6, where in the ip nat translation table there is the association inside local/inside global, and the echo replay goes to R4..... all work fine for me..... where i wrong?????

well i wont go deep in this coz ull get confused , take it like this
R4 pings R7 , the packet goes from fa0/1 on R4 to R6 AS 172.16.11.70( the packet reached 172.16.11.0/24 so we can reach R7) all this is the echo request , BUT the echo reply wont be done unless R7 knows how to reach R4 and as you notice in its routing table there isnt any entry for R4 so it wont work even if the NAT is there

if you run on router 5 the show ip route command you must have a static route to R4 !

what i want u to know is if you have NAT that doesnt mean PING can work , you must have a route to reach the destination , i hope im explaining right
any other member can confirm that im a master of ccna lol

First you say that R4 has the ip 172.16.6.14 (i supposed you want do NAT in R6), and then you say that R5 has a static route to R4 so it can send the echo replay?????

Sorry but if in the echo request that arrived to R5 we have as source ip 172.16.6.14, in the echo replay we must have as destination ip 172.16.6.14...... If in R5 we have a static route to R4 (ip address10.10.10.4) how R5 can sand echo replay if it hasn't a route to 10.10.10.4 ?????




For the R4 <-> R5 connection there is no need any static route as R5's fa0/0 (172.16.6.6/24) and R4's NATed fa0/1 (172.16.6.14/24) are in the same subnet.

R4's fa0/1 IP address for R5 and R7 is 172.16.6.14 not 10.10.10.4.



@sacred and wont R4 have the same IP of 172.16.11.70 related to R7 ( according to the dynamic NAT ) ? so it will be in the same subnet as well

@concico that what im trying to explain for you , of course all wat im explainaing for you is based of what i know so you will have a confirmation from others as well and in case im wrong they will correct me

just get one point in your mind :
NAT DOESNT MEAN YOU CAN PING ! , yes it do the NAT and it translates the addresses but it doesnt mean to give you ping ability to let the packet transfer from a source to a destination or vice versa
the question is telling u the we can ping R5 , that is ok so dont bother urself with that ( if you run a show ip route command on that router YOU will find a route to R4 network ! )
and we need the same on R7 EVEN IF THE NAT IS CORRECT

i hope you got it

@concico

the purpose of a static route is to allow the router to have a map of not connected IP addresses...............unless the router doesn't have tht IP address in it's routing table it wont let the packet pass through it to it's destination....................


creeeeeem, BUT the 24 bit mask means that 172.16.6.14 and 172.16.11.70 are in diferrent subnets. Right?


ya so ?

after re-reading the question i would like to comment further that the NATTING being performed on R6 is not correct either Statically or in Dynamically

Problem found in Static NAT.

it is Translating to the interface that doesnot exits and is considered wrong according to me. 172.16.6.14.

Problem in Dynamic NAT

it has a pool of addresses that doesnot include 10.s network and a wrong range for 172s network


As its mentioned in question itself that the Router 4 has default gateway configured as R6. it means there must be a Static Route entry for network related to R4

Correct Option is C without any doubts, as NAT is totally non-funtional in this configuration, only we need to set a Static Route on R7 and configure R6 as Default Gateway same in R4



Router R4 is reaching to R5 all the way is through a Static Route entry not by NATTING (NAT IS WRONG), which R7 is missing. if you set R7 same as R4 is set using a static route and a default gateway R4 can reach R7 aswell.




I think that static nat is working good, for the communication between R4 and R5, why you say it doesn't...???
Why is necessary configure also R6 as Default Gateway (same in R4) in R7 ????

read my comment on page 1


dude can u read my comment ? i think it explains wat u want exactly




you have written:

[b]just get one point in your mind :
NAT DOESNT MEAN YOU CAN PING ! , yes it do the NAT and it translates the addresses but it doesnt mean to give you ping ability to let the packet transfer from a source to a destination or vice versa
the question is telling u the we can ping R5 , that is ok so dont bother urself with that ( if you run a show ip route command on that router YOU will find a route to R4 network ! )
and we need the same on R7 EVEN IF THE NAT IS CORRECT [/b]


I'm not sure of this........

why is necessary a static route in R5 to R4?????
I'm agree with sacredboy that as written


For the R4 <-> R5 connection there is no need any static route as R5's fa0/0 (172.16.6.6/24) and R4's NATed fa0/1 (172.16.6.14/24) are in the same subnet.