Solved

ACLs on virtual interfaces

Posted on 2010-09-17
6
557 Views
Last Modified: 2012-05-10
I have several VLANs defined on a stack of Cisco Catalyst 3750 switches.  (Layer 3).    IOS version is 12.2(25)SEE2)

I'm trying to do something that seems pretty simple, and I'm hopefully missing something obvious.

I want to prevent one VLAN from having any access to the other.   (ip routing is turned on, and it needs to be on.)   I followed another example I found online, and it seems like it should work.   The config lines are below.  I'm trying to prevent VLAN 99 from accessing VLAN 11 by using an ACL.   Address ranges are:  VLAN 11   10.67.11.0/24    VLAN 99  10.67.99.0/24

 interface Vlan11
 ip address 10.67.11.247 255.255.255.0
 ip access-group BAN_VLAN99 in


interface Vlan99
 ip address 10.67.99.247 255.255.255.0


ip access-list extended BAN_VLAN99
 deny   ip 10.67.99.0 0.0.0.255 any
 permit ip any any


But if I put a VLAN 99 address on a workstation, and plug into a VLAN 99 port, I'm still able to ping addresses on VLAN 11   (10.67.11.1 for example)

This seems embarrassingly simple... what am I missing??
0
Comment
Question by:asd-dave
6 Comments
 
LVL 3

Expert Comment

by:kf4zmt
Comment Utility
Change this:  ip access-group BAN_VLAN99 in
to this: ip access-group BAN_VLAN99 out


Or better yet, modify your ACL and apply it as an inbound ACL on the vlan 99 interface.
0
 
LVL 22

Expert Comment

by:Matt V
Comment Utility
Have you applied the lists to the interfaces?  Also, this seems like a routing issue, the ACL should be applied where the routing is taking place.
0
 
LVL 22

Expert Comment

by:Matt V
Comment Utility
Nevermind, I missed the application on the interface.
0
How your wiki can always stay up-to-date

Quip doubles as a “living” wiki and a project management tool that evolves with your organization. As you finish projects in Quip, the work remains, easily accessible to all team members, new and old.
- Increase transparency
- Onboard new hires faster
- Access from mobile/offline

 
LVL 3

Expert Comment

by:kf4zmt
Comment Utility
Like this

ip access-list extended BAN_VLAN99
 deny   ip any 10.67.11.0 0.0.0.255
 permit ip any any

interface Vlan99
 ip access-group BAN_VLAN99 in
0
 
LVL 24

Expert Comment

by:rfc1180
Comment Utility
or:

interface Vlan99
 ip access-group DENY_VLAN11 in

ip access-list extended DENY_VLAN11
 deny   ip 10.67.99.0 0.0.0.255 10.67.11.0 0.0.0.255
 permit ip any any

Billy
0
 
LVL 17

Accepted Solution

by:
Kvistofta earned 125 total points
Comment Utility
You have to think the other way around. You have an acl inbound on int Vlan11, which means that you at that point can filter traffic coming INBOUND into the router, FROM that interface. You block 10.67.99.0 source-addresses in that acl but on that interface and in that direction there will never come any traffic source from that addresses.

If you want to stop vlan 99 from accessing vlan 11 you should place an inbound acl on int vlan 99 instead, blocking traffic from vlan 11 ip addresses:

int vlan99
 ip access-group BAN_VLAN11 in
!
ip access-l ext BAN_VLAN11
 deny ip 10.67.11.0 0.0.0.255 any
 permit ip any any
!

Another option is to place the acl outbound instead of outbound, by using the "out"-parameter in the access-group interface-command.

/Kvistofta
0

Featured Post

Enabling OSINT in Activity Based Intelligence

Activity based intelligence (ABI) requires access to all available sources of data. Recorded Future allows analysts to observe structured data on the open, deep, and dark web.

Join & Write a Comment

#Citrix #Citrix Netscaler #HTTP Compression #Load Balance
Join Greg Farro and Ethan Banks from Packet Pushers (http://packetpushers.net/podcast/podcasts/pq-show-93-smart-network-monitoring-paessler-sponsored/) and Greg Ross from Paessler (https://www.paessler.com/prtg) for a discussion about smart network …
Here's a very brief overview of the methods PRTG Network Monitor (https://www.paessler.com/prtg) offers for monitoring bandwidth, to help you decide which methods you´d like to investigate in more detail.  The methods are covered in more detail in o…
In this tutorial you'll learn about bandwidth monitoring with flows and packet sniffing with our network monitoring solution PRTG Network Monitor (https://www.paessler.com/prtg). If you're interested in additional methods for monitoring bandwidt…

762 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question

Need Help in Real-Time?

Connect with top rated Experts

11 Experts available now in Live!

Get 1:1 Help Now