We help IT Professionals succeed at work.

Check out our new AWS podcast with Certified Expert, Phil Phillips! Listen to "How to Execute a Seamless AWS Migration" on EE or on your favorite podcast platform. Listen Now

x

Configure ingress & egress ACL's on cisco 2811

MikeG299
MikeG299 asked
on
Medium Priority
1,044 Views
Last Modified: 2012-05-07
Hello, I've configured a cisco 2811 for a 56k frame-relay circuit on a private network. One of the security requirements is to setup ingress & egress ACL for inbound/outbound traffic. Can't say i've attempted this yet. I'll have to do all the configuration changes via telnet since the router is at another location. I'll post the configuration I have below (its pretty basic). Any help would be most appreciated. Thanks!




!
version 12.4
service timestamps debug datetime msec
service timestamps log datetime msec
no service password-encryption
!
hostname <!>
!
boot-start-marker
boot-end-marker
!
enable password <!>
!
no aaa new-model
!
!
ip cef
!
!
multilink bundle-name authenticated
!
!
!
archive
 log config
  hidekeys
!
!
!
!
!
interface FastEthernet0/0
 ip address <!> 255.255.255.0
 duplex auto
 speed auto
!
interface FastEthernet0/1
 no ip address
 shutdown
 duplex auto
 speed auto
!
interface Serial0/0/0
 no ip address
 encapsulation frame-relay IETF
 no fair-queue
!
interface Serial0/0/0.777 point-to-point
 ip address 192.168.<!> 255.255.255.252
 snmp trap link-status
 frame-relay interface-dlci 777
!
no ip forward-protocol nd
ip route 0.0.0.0 0.0.0.0 192.168.<!>
!
!
ip http server
!
!
!
control-plane
!
!
line con 0
 password <!>
 login
line aux 0
line vty 0 4
 password <!>
 login
!
scheduler allocate 20000 1000
!
end
Comment
Watch Question

atlas_shudderedSr. Network Engineer
CERTIFIED EXPERT

Commented:
Have you got a TFTP server on the customer's side?

Author

Commented:
No, I do not. I only need to control inbound/outbound ports from 56kwic to fe/0.
atlas_shudderedSr. Network Engineer
CERTIFIED EXPERT

Commented:
Okay.  Before you start with the ACL I would secure your vty session with ssh and dump telnet.  (Before you disable telnet, confirm that ssh is working and you can connect successully).  Another thing that I would recommend is, starting any changes on a remote router, be sure to issue the command:

#reload 005

This instructs the router to perform a reload in 5 minutes, this way, if you make a change and lose connectivity to the router, the change will be dropped at reload, allowing access again.  Once you are done with your configs, issue the command:

#reload cancel

if more time is needed, follow the above with #reload 005 again.

Finally, try to do as much as you can in notepad and then upload.  Otherwise, you will have to keep saving your work to flash and resetting the reload command if more time is needed.

After you have set up ssh, open notepad and configure your ACLs (if you have ideas of what exactly you want the ACL to filter, post that and I will try to work up an example.)  Build them from the perspective of:

Traffic coming to the LAN from your FR link should be filtered on serial 0/0/0.777 in
Traffic leaving the LAN destined for another network should be filtered on eth 0/0 in

Doing this limits the traffic that is actually processed for routing to only that traffic which is going to be allowed across the circuit to begin with.

Once your ACLs are built, copy and paste them into the router (don't apply them).
Next, apply the ACL that is limiting traffic to the WAN first and tweak it as needed.
Following this, issue the #reload 005 command and apply the second ACL to the serial 0/0/0.777 link.  

Perform a #show run.  If output is returned, breathe a sigh of relief, save to flash and start your review and tweaking.  If not, go get a coke and become scarce for the next 5 minutes.  Upon return, review the ACL for what is locking your remote access and repeat.

Author

Commented:
Hi,
Thanks so much for responding.
I've never setup SSH, could you please post an example or some sort of instruction?

The router is on a private network managed by AT&T. There is no WAN or exposure to the WWW.

ON the ACL: I want to allow only sessions over port 3389 in/out, PING in/out, 502 in/out

Thats a great idea on the reload 005. Look forward to your reply.
Sr. Network Engineer
CERTIFIED EXPERT
Commented:
Unlock this solution with a free trial preview.
(No credit card required)
Get Preview

Author

Commented:
Got it working. Thanks so much; very appreciated.
Unlock the solution to this question.
Thanks for using Experts Exchange.

Please provide your email to receive a free trial preview!

*This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.

OR

Please enter a first name

Please enter a last name

8+ characters (letters, numbers, and a symbol)

By clicking, you agree to the Terms of Use and Privacy Policy.