Category Archives for "Packets Analyzed"

DNS Packet

The Naked DNS Packet

The above shows the DNS Opcodes in a DNS request.

Additional insight into the packet - As you can see that the DNS server responding was not authoritative and supported recursion.

The Journey Starts 2014 – CCIE Security – Blog Post1

Well it is time to buckle down and make it happen in 2014. The goal is to become a dual CCIE by the end of 2014. I have previously passed the CCIE Sec written in version 3 but I did not have the time to actually sit for the lab and I also wanted to refresh to the latest version of the track. That said I am taking a small step back to refresh and reinforce the theory. The plan is to go through the NP Security track while labbing but also taking the respective NP exam followed by the written and then ultimately sit for the lab.

Here is the order as it stands today:
  • 642-627 IPS - Implementing Cisco Intrusion Prevention System 
  • 642-618 FIREWALL - Deploying Cisco ASA Firewall Solutions 
  • 642-648 VPN - Deploying Cisco ASA VPN Solutions 
  • 642-637 SECURE - Securing Networks with Cisco Routers and Switches
  • ISE and WSA 
  • CCIE Written 
  • CCIE Lab
The primary partner that I am leveraging is CiscoPress and Cisco Docs for the theory and iPexpert for all the heavy labbing. 

The great thing about this journey is that I already eat, sleep, and breath Cisco .:|:.:|:.

Twitter: FE80CC1E

Control Plan and Data Plan – Answer provided by Keith Barker

I came across this great answer to a question from Keith Barker and felt it needed to be shared. Great analogy Keith.

Hello Vijay-

Great question.

Let's say you and I are in charge of public transportation for a small city.

transportation routes.gif

Before we send bus drivers out, we need to have a plan.

Control Plane = Learning what we will do

Our planning stage, which includes learning  which paths the buses will take, is similar to the control plane in the network.   We haven't picked up people yet, nor have we dropped them off, but we do know the paths and stops due to our plan.  The control plane is primarily about the learning of routes.

In a routed network, this planning and learning can be done through static routes, where we train the router about remote networks, and how to get there.   We also can use dynamic routing protocols, like RIP, OSPF and EIGRP to allow the routers to train each other regarding how to reach remote networks.   This is all the control plane.

Data Plane = Actually moving the packets based on what we Continue reading

RFC 3330 Filtering Using Network Objects

RFC3330 Special-User IPv4 Addresses

Below is a list of special use IPv4 address assigned by IANA and should be blocked inbound on external connections. Most security administrators block RFC1918 but do not realize that RFC3330 includes special use addresses that should not be traversing the internet. RFC3330 includes addresses referenced in multiple RFC's including RFC1918.

   Address Block             Present Use      
   --------------------------------------------------            "This" Network                   Private-Use Networks                       Public-Data Networks             Cable Television Networks                     Reserved but subject to allocation                                  Loopback                      
  Continue reading

HP Route Preference (Administrative Distance)

When building networks leveraging a variety of products you need to consider interoperability and configuration consistency. When leveraging HP A-Series switches in a Cisco environment considerations need to be made in regards to administrative distance (Cisco's term) or route preference (HP's term). In order to ensure that you maintain consistent behavior it is recommended that you modify one or the other and make them consistent with each other. I would recommend following Cisco's administrative preference instead of HP's route preference.

HP's default route preference

Cisco's default administrative distance

Don't get caught with unexpected routing behaviors. Have fun!


I have talked with a few security administrators that seem to struggle with the understanding of FN, TN, FP, TP. I have decided to try to create a simple method to remember.

True/False = This either CORRECTLY or INCORRECTLY identifies an attack
Positive/Negative = This performs and event that takes an ACTION or is ACTION-LESS

True Positive (TP) - A legitimate attack (CORRECTLY) which triggers an IDP to produce and alarm/alert or mitigate the risk (ACTION)

False Positive (FP) - An IDP believes there is an attack taking place (INCORRECTLY) and produces an alarm/alert or mitigates the risk (ACTION).This can cause disrupt legitimate traffic and flood your IDP with alerts drowning real alerts that may be taking place. Some traffic that may cause false positives include:

  • Legitimate applications that do not follow RFC's 
  • Legitimate traffic in one part of an organization that may not follow normal behaviors in another part of the organization causing alerts. 
  • Signatures that we written poorly and identify both legitimate and illegitimate traffic. 

False Negative (FN) - There is an attack that has NOT been identified (INCORRECTLY) and no alarm/alert/mitigation was raised (ACTION-LESS). This causes a false sense of security. This can be caused for a variety Continue reading

Testing AAA Authentication with ACS – Part 1

Confirming that local authentication on the switch and ACS is working after you finished your configuration perform the following:

Run the "test" command on the switch
sw1#test aaa group tacacs+ ro PASSWORD legacy
Attempting authentication test to server-group tacacs+ using tacacs+
User was successfully authenticated.

sw1#test aaa group tacacs+ admin99 PASSWORD legacy
Attempting authentication test to server-group tacacs+ using tacacs+
User authentication request was rejected by server.

Even though the second attempt was rejected it still confirms that ACS rejected the request and is fully operational.

Step 1. Lets have a look at the ACS server. Once logged in navigate to "Monitoring and Reports" and click  "Launch Monitoring and Report Viewer"

Step 2. A new window pops up. Navigate to "Reports", "Catalog", and click "AAA Protocols".

Step 3. On the right pain under reports click "TACACS Authentication. As you can see the first 2 entries correlate to what was seen on the switch. A pass and a fail.

Step 4. Lets look at some more details by clicking the magnifying glass under details. Lets look at the authentication that passed. As you can see there is alot of details. The big thing here is the "Status"

Step 5. Lets look Continue reading


Its been a while but I am going to try to post weekly.

Here is a sample configuration for IPSEC VPN between in 2 routers.
Note: 172.16.1.X/32 are loopback interfaces.

Define IKE Phase 1 Policy (ISAKMP)
(config)#crytpo isakmp policy 10
(config-isakmp)#encryption aes 256
(config-isakmp)#authentication pre-share
(config-isakmp)#hash sha
(config-isakmp)#group 2

Define pre-shared key
(config)#crypto isakmp key 0 [email protected]$ address

Define IKE Phase 2 Policy (IPSEC)
(config)#crypto ipsec transform-set TRANS-R1-R2 esp-aes 256 esp-sha-hmac

Create ACL to match interesting traffic
(config)#access-list 150 permit ip

Create Crypto Map
(config)#crypto map VPN-MAP-R1-R2 10 ipsec-isakmp
(config-crypto-map)#set peer
(config-crypto-map)#set transform-set TRANS-R1-R2
(config-crypto-map)#match address 150

Apply Cypto Map to Interface
(config)#interface fas0
(config-if)#crypto map VPN-MAP-R1-R2

Create a route
(config)#ip route fas0

Define IKE Phase 1 Policy (ISAKMP)
(config)#crytpo isakmp policy 10
(config-isakmp)#encryption aes 256
(config-isakmp)#authentication pre-share
(config-isakmp)#hash sha
(config-isakmp)#group 2

Define pre-shared key
(config)#crypto isakmp kep 0 [email protected]$ address

Define IKE Phase 2 Policy (IPSEC)
(config)#crypto ipsec transform-set TRANS-R1-R2 esp-aes 256 esp-sha-hmac

Create ACL to match interesting Continue reading

CCIE Security

I have just successfully passed the CCIE Security written exam at Cisco Live 2012. The exam was no cake walk and was very challenging. Although I studied all the material from the CCNP security track and read the Network Security Technologies and Solutions (CCIE Professional Development Series) book I did not take any of the CCNP Security exams. I took a little different approach to this CCIE then I took in the R&S track. I will be starting to do the practice labs and will go back to theory throughout the process to do each of the CCNP Security exams. I am hoping that this ensures that I perform the practice labs without fail and continue to cement the theory throughout the process.


Logging – Levels

There are 8 different logging levels. Enabling higher level messages enables all lower level messages. EX: enabling Debugging level 7 enables all messages.

Level     Level Name         Description                                     Syslog Definition
0           Emergencies         The system is unusable                    LOG_EMERG
1           Alerts                   Immediate action is needed             LOG_ALERT
2           Critical                 Critical condition                             LOG_CRIT
3           Errors                  Error condition                                LOG_ERR
4          Warnings              Warning Condition                           LOG_WARNING
5     Continue reading