Still celebrating National IT Professionals Day with 3 months of free Premium Membership. Use Code ITDAY17

x
?
Solved

Cisco SPAN Configuration

Posted on 2011-09-08
10
Medium Priority
?
1,266 Views
Last Modified: 2012-05-12
We are using Websense to monitor and filter web traffic so we setup SPAN session to monitor web traffic on the Catalyst switch stack and everything was working fine then we upgraded Websense to 7.6 and upgraded the switch's IOS to 15.0 and after a while it stopped working.
I just wanted to know if I am now required to insert a new piece of code to the existing one because the SPAN configuration is not working. This is what I had to make the port a SPAN monitoring port:

monitor session 1 source interface FastEthernet1/0/1
monitor session 1 destination interface FastEthernet1/0/15 encapsulation replicate

Both are in the default same VLan
this is the output of sho monitor

Type : Local Session
Source Ports :
Both : Fa1/0/1
Destination Ports : Fa1/0/15
Encapsulation : Native
Ingress : Disabled
0
Comment
Question by:Maximus54
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
  • 6
  • 2
  • 2
10 Comments
 
LVL 22

Expert Comment

by:eeRoot
ID: 36506984
Your config appears correct.  Is it possible that the websense unit lost a settings in its config due to the upgrade?  Also, verify that port 15 did not shut down for some reason.
0
 

Author Comment

by:Maximus54
ID: 36507726
eeRoot, I have removed and uninstalled Websense and checked all of the settings and I dont think that is the problem. I suspected that it was the SPAN setting, I did a check on the destination port to see if traffic was being sent there( #show int Fa1/0/15 summary) and the Rx(ingress) shows up as 0 when the source port show more numbers. It sounds that the destination port is not getting any Rx traffic or is the Rx supposed to be 0.
0
 
LVL 22

Accepted Solution

by:
eeRoot earned 1000 total points
ID: 36508215
Rx would be 0 because nothing is coming into the port from the Websense.  Although I've never heard of a monitor seession getting locked up, you may want to remove and re-add it.  Also, there is a piece of software called Wireshark, you can load it onto a laptop and then connect the laptop to the Fa1/0/15 interface and see if Wireshark shows any packets being sent out.  If not, then the problem lies with the switch
0
Automating Your MSP Business

The road to profitability.
Delivering superior services is key to ensuring customer satisfaction and the consequent long-term relationships that enable MSPs to lock in predictable, recurring revenue. What's the best way to deliver superior service? One word: automation.

 

Author Comment

by:Maximus54
ID: 36510524
eeRoot, good idea. I will try and let you know. thanks
0
 
LVL 8

Expert Comment

by:amatson78
ID: 36511378
I would run a wireshark test but if you are using the SPAN port for the Websense Network Agent there will be no return traffic because the Network Agent only "Sniffs" which is why it is not required to have an IP address. It is only a monitor port. Is this a Standalone Websense Install?
0
 

Author Comment

by:Maximus54
ID: 36511676
I did plug in wireshark and it is picking up traffic after I took out the encapsulation replicate portion of the code from the destination port. In fact I am getting Request, Blocked and RTSU numbers on Websense counters but it is still not blocking. I have 2 NIC cards, both are configured with IP addresses, the NIC 1 connected to the listening port only has an IP and Mask (No gateway or DNS) and the NIC 2 connected to the destination has all the IP configuration in it. I set up NIC 1 as the monitoring NIC and NIC 2 as the blocking NIC. is there something wrong with the setup. It used to work.
And yes it is a standalone Websense install.
0
 

Author Comment

by:Maximus54
ID: 36511707
That's strange after I took out the encapsulation replicate portion in the switch code, the Real-Time Monitor mode works and I can see traffic which I was not able to before. Let me flip the blocking NIC
0
 
LVL 8

Assisted Solution

by:amatson78
amatson78 earned 1000 total points
ID: 36511734
I am not a cisco guru by any means but I know Websense works with just the default span command. Like you said you have a blocking NIC and a monitoring NIC. The monitoring NIC just sits there and listens to the incoming traffic. If it cannot see or read the traffic then it will not be able to perform its job.:)
0
 

Author Comment

by:Maximus54
ID: 36511744
SO amatson78, should I also make the monitoring NIC the Blocking NIC then, I have not done it yet as I do not want to mess it up since part of is now working.
0
 

Author Comment

by:Maximus54
ID: 36511805
Never mind it works now, I guess the solution is to take out the encapsulation replicate portion, this may be due to the IOS 15.0 upgrade. I left the NICs as is and it works One monitors, the other blocks. Thanks for all of your help guys, you lead me in the right direction.
0

Featured Post

Introducing the WatchGuard 420 Access Point

WatchGuard's newest access point includes an 802.11ac Wave 2 chipset, providing the fastest speeds for VoIP, video and music streaming, and large data file transfers. Additionally, enjoy the benefits of strong security as the 3rd radio delivers dedicated WIPS protection!

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Check out the latest tech news, community articles, and expert highlights in August's newsletter.
If you're a modern-day technology professional, you may be wondering if certifications are really necessary. They are. Here's why.
With Secure Portal Encryption, the recipient is sent a link to their email address directing them to the email laundry delivery page. From there, the recipient will be required to enter a user name and password to enter the page. Once the recipient …
We’ve all felt that sense of false security before—locking down external access to a database or component and feeling like we’ve done all we need to do to secure company data. But that feeling is fleeting. Attacks these days can happen in many w…

670 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