Tuesday, June 30, 2015

Packet Capture: Is Traffic Being Encrypted On My Check Point Appliance

This post deals with a recent issue I had were a Check Point firewall was not encrypting traffic when it need to.  Now I like CLI better, as most people know.  So I pulled up the CLI to do a packet capture of what was going on.  Im on a 4800 Check Point appliance.  I want to see if my remote client 192.168.10.X network is getting to the 192.168.7.X remote network.  192.168.7.X network is across a site to site VPN from my Check Point 4800.  My mobile client sits at home, VPN'ed into the 4800.

With that said, I found that the traffic was not being encrypted.  Below is a snipped of what I saw that tipped me off:
[Expert@CP-N2:0]# fw monitor -e "accept host(192.168.10.1) and ip_p=1;"
 monitor: getting filter (from command line)
 monitor: compiling
monitorfilter:
Compiled OK.
 monitor: loading
 monitor: monitoring (control-C to stop)
[vs_0][fw_0] eth1:i[60]: 192.168.10.1 -> 192.168.7.54 (ICMP) len=60 id=13108
ICMP: type=8 code=0 echo request id=1 seq=56
[vs_0][fw_0] eth1:I[60]: 192.168.10.1 -> 192.168.7.54 (ICMP) len=60 id=13108
ICMP: type=8 code=0 echo request id=1 seq=56
[vs_0][fw_0] eth1:o[60]: 192.168.10.1 -> 192.168.7.54 (ICMP) len=60 id=13108
ICMP: type=8 code=0 echo request id=1 seq=56
[vs_0][fw_0] eth1:O[60]: 192.168.10.1 -> 192.168.7.54 (ICMP) len=60 id=13108
ICMP: type=8 code=0 echo request id=1 seq=56

Notice highlighted above, it goes through all four phases of traversing the Check Point.  Now, below, you will see that I resolved the issue and the packet capture looks different.
[Expert@CP-N2:0]# fw monitor -e "accept host(192.168.10.1) and ip_p=1;"
 monitor: getting filter (from command line)
 monitor: compiling
monitorfilter:
Compiled OK.
 monitor: loading
 monitor: monitoring (control-C to stop)
[vs_0][fw_0] eth1:I[60]: 192.168.10.1 -> 192.168.7.54 (ICMP) len=60 id=15346
ICMP: type=8 code=0 echo request id=1 seq=68
[vs_0][fw_0] eth1:o[60]: 192.168.10.1 -> 192.168.7.54 (ICMP) len=60 id=15346
ICMP: type=8 code=0 echo request id=1 seq=68
[vs_0][fw_0] eth1:I[60]: 192.168.10.1 -> 192.168.7.54 (ICMP) len=60 id=15348
ICMP: type=8 code=0 echo request id=1 seq=69
[vs_0][fw_0] eth1:o[60]: 192.168.10.1 -> 192.168.7.54 (ICMP) len=60 id=15348
ICMP: type=8 code=0 echo request id=1 seq=69

Now, I dont have the problem fixed, but I at least see the traffic being encrypted coming from the mobile client, which is better than before.  See above, how it only traverses 2 phases instead of 4.

This is a good way, in CLI, to know if a packet is being encrypted or not on the Check Point appliance.

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