Good read: Do you block ICMP at all places in Network?

If your answer is Yes, or you believe that blocking ICMP increases security, then please give some second thoughts for the poor support guy who gets called at 2 A.M. and needs to ping some hosts to ensure reachability….

The Problem

Many network administrators feel that ICMP is a security risk, and should therefore always be blocked at the firewall. It is true that ICMP does have some security issues associated with it, and that a lot of ICMP should be blocked. But this is no reason to block all ICMP traffic!

ICMP has many important features; some are useful for troubleshooting, while some are essential for a network to function correctly. Here are details of some of the important ICMP traffic that you should know about, and consider allowing through your network.

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Why SSL Inspection matters?

Having SSL Inspection has been always a matter of IT and Organisation fight.
In an architecture project, the only objection to my design was SSL Inspection and I had to bring some convincing reasons for that.

First of all, without SSL Inspection, basically there is zero visibility into what’s happening inside an encrypted traffic like HTTPS, SMTPS, POP3S, etc. Just imagine an attacker popping a machine, tunneling command and control via a HTTPS tunnel. Or an unfortunate employee, exposing confidential data by uploading them to some random cloud service… 0 visibility!

Second business driver I can think of is related to Data Loss Prevention; If a breach is detected tomorrow, there’s hardly any ways to detect what has been lost.

Benefits aside, a noteworthy drawback to SSL Inspection would be administrative overhead; you should distribute the CA cert to all nodes. That being said, in case of a Directory environment like Microsoft AD, it’s not a big deal, although Linux machines or some browsers need special configuration; beside, some web applications have to be excluded from inspection, mainly the ones utilizing Java.

Not really a drawback, but the administrators should be liable and trusted as they can easily intercept the traffic, unencrypted. This not only applies to the Proxy admins, but to a Mail admin, System admin, etc; which makes it an HR matter.
Note that any product which does MITM has the opportunity to expose data, and so its admins.

Here, you have to see the tradeoff; I believe the gained visibility worths it!

Sometimes CxOs might say that SSL is sacred! Yes, it is, but they have to decide how sacred they want SSL to be versus how interested they are in what information might be leaving the environment without authorization; or how much malware command and control (C&C) they might want quietly going out via SSL without being torn open for inspection.

Note that you have to design a way that all egress web traffic (both users and servers) must be enforced to go through the proxy, otherwise the whole proxy plan is pointless. Besides, you have to follow some practices:

  • Know the business and business processes and demands. Every sector has its own limitations or requirements where might be against SSL inspection.
  • Plan some whitelisting policies to disable inspection in specific cases where needed.
  • Know your traffic and the percentage of encrypted requests.
  • Make sure that your appliance supports the amount of traffic; SSL Inspection means decrypting the connection, inspecting it and then re-encrypting it.

P.S. Yes, my drawing skills are awful! ?

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Check Point CCSE Notes

Following my post on Check Point CCSA Exam notes, in this post I’m gonna write notes on CCSE exam. Though this time I won’t fall into configuration and try to only point out the more important and real-world-applicable things.

Management Server HA

  • When adding a new Check Point host as a Secondary Management Server, do not Initialize SIC before selecting Network Policy Management feature!
  • After adding the host, save and Install the policy; synchronization will then work.

As a reminder, whenever you reset the SIC for a Gateway from Management Server, it should be re-initialized from the Gateway by cpconfig; don’t forget to exit cpconfig!


Check Point calls its clustering solution ClusterXL which supports up to 8 Cluster members and can be implemented in two main flavors:

  1. Load-sharing
    • Multicast mode: 50/50, very efficient and excellent performance
    • Unicast mode: 70/30, to be used in environments where an intermediate device has issues with multicast MAC address (IGMP Snooping)
  2. High Availability (HA)
    • New Mode: Each member has its own physical IP address
    • Legacy Mode: Both members have the same physical IP address

To make kernel changes permanent, they should be written in $FWDIR/modules/fwkern.conf

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Check Point CCSA Notes

CheckPoint is the largest pure-play security vendor globally, and has a long history of being a respected security solutions provider and the company’s devices are one of the most deployed firewalls in use today.

Till now, for eighteen consecutive years Check Point has been positioned in the “Leaders” quadrant in the Magic Quadrant for Enterprise Network Firewalls. Check Point is also positioned in the “Leaders” for Unified Threat Management (UTM) for five years till now. Gartner evaluates each vendor’s Enterprise Network Firewall offerings on a scale of completeness of vision and ability to execute.

Traffic Control Methods:

  • Packet Filtering in OSI Layer 3 (Network) and Layer 4 (Transport)
  • Stateful control by Inspect Engine, again at L3 and L4 but with more focus on L4
  • Application Awareness

Check Point Operating system:

We talk here about both Management Server and the Gateways (firewalls) OS.

  • IPSO was the initial version, based on BSD (Nokia’s IPSO).
  • SecurePlatform (SPLAT), based on Redhat
  • GAiA is the latest version!

Deployment Notes

With small environments, it’s possible to have the Management Server and Gateway on the same hardware. This is called Standalone deployment.

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