02-05-2011 12:50 PM - edited 03-06-2019 03:22 PM
I'm studying for my CCNA, and I'm having a TERRIBLE time figuring out ACL's. I'm in Packet Tracer, and one of my labs goes like this:
R A N E T CO.,LTD.
LAB 4-6: Access Control List (ACL)
You are the network administrator at Ranet, and
have to config router Ranet-HQ to connect its LAN
to Branch network and Internet, and to config
Access-List to control traffic as below:
(via its console)
1. Enable and set IP address on LAN interface
to be the first assignable IP of this subnet.
2. Enable and set IP address on each serial
interface to be the last assignable IP of its
own subnet.
3. Set RIPv2 to be the router protocol on this
router to exchange route with Ranet-BR
4. Set default route to allow the connection with
internet.
5. Set access-list to prevent the connection
from hosts in LAN as:
- allow only Admin-Host to telnet to
Ranet-CoreSW (password: ranetpass)
- Not permit only User-Host1 to connect
to any site in the internet.
- Any traffic beside these should be allow.
Remark: Use ACL no.100 only!, and use as short
as possible to gain %Completion
Here's the network:
I got it wrong. I get everything right but the ACL part. I can't figure out how to do this. Here's what I made...can someone tell me what I'm doing wrong?
interface FastEthernet0/0
ip address 172.22.3.33 255.255.255.224
ip access-group 100 in
duplex auto
speed auto
!
interface FastEthernet0/1
no ip address
duplex auto
speed auto
shutdown
!
interface Serial0/0/0
ip address 172.22.3.98 255.255.255.252
!
interface Serial0/1/0
ip address 203.144.7.254 255.255.255.252
!
interface Vlan1
no ip address
shutdown
!
router rip
version 2
network 172.22.0.0
network 203.144.7.0
!
ip classless
ip route 0.0.0.0 0.0.0.0 Serial0/1/0
!
!
access-list 100 permit tcp 172.22.3.32 0.0.0.31 172.22.3.64 0.0.0.31 eq telnet
access-list 100 deny ip host 172.22.3.53 any
02-05-2011 10:31 PM
access-list 100 permit tcp host 172.22.3.50 host 172.22.3.90 eq telnet <<---to allow Admin-host to telnet to core sw
access-list 100 deny tcp any any eq telnet <<----- to block other sources from telnetting to Ranet-CoreSw
- Not permit only User-Host1 to connect to any site in the internet.
access-list 100 deny tcp host 172.22.3.53 any eq www
- Any traffic beside these should be allow.
inbound ACL on Fa0/0 on Ranet-HQ
Let me know if this works.
02-06-2011 09:04 AM
That didn't work...one question though: why would this statement be necessary?
access-list 100 deny tcp any any eq telnet <<----- to block other sources from telnetting to Ranet-CoreSw
Wouldn't the implicit deny any accomplish what this statement is trying to do? Because any host not matching the permit telnet statement above it would fall through to the implicity deny any...
02-06-2011 09:06 AM
Yes the implicit deny should block everything includng telnet and this statement is optional
Cheers,
Shashank
P.S. Please rate helpful posts
02-06-2011 09:23 AM
okay, my bad. I missed out on the
access-list 100 permit ip any any
at the end of the ACL.
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