Can I run 'apt-get update' on NAC appliance?


Userlevel 5
Hi, In the process of creating some DHCP fingerprints for NAC devices that are not showing up. The best why to do this would be to run dhcpdump on the NAC server and record the details given in option 55 and write the fingerprint to match. Problem is when running 'apt-get install dhcpdump', I get the following error: E: The package libc6 needs to be reinstalled, but can't find an archive for it. In order to run dhcpdump you require the following packages: libc6 >= 2.4 libpcap0.8 >= 0.9.3-1 Running an 'apt-cache policy libc6' shows that the current version is 2.15. So I beleive I need to run an apt-get update in order to bring everything to the versions I need. So my question is, is this safe to do on a NAC apliance? NetSight is running version 6.3.0.168 and OS is Ubuntu 12.04 LTS Many thanks in advance.

3 replies

Userlevel 7
I've done it on my Netsight to run some Expect scripts and there is a KB articel that sugests that it's allowed - haven't done it on the NAC as it wasn't a requirement yet for me.

https://community.extremenetworks.com/extreme/topics/run-expect-in-netsight
https://gtacknowledge.extremenetworks.com/articles/How_To/How-to-disable-enable-wireless-services-du...

Here a KB article how to get the fingerprint information with the tcpdump command...
https://gtacknowledge.extremenetworks.com/articles/How_To/NAC-Troubleshooting-Tips-Debug-Methodology...

-Ron
Userlevel 5
Thats a fanastic answer, thanks, let me test and post back if it did the trick! Cheers
Userlevel 5
Martin Flammia wrote:

Thats a fanastic answer, thanks, let me test and post back if it did the trick! Cheers

I had 'IP Helper' enabled but also had to configure 'ip forward-protocal bootps' in order to see the DHCP options come through to the NAC. There was also no need to do a tcpdump as using the verbose diagnostics listed in the gtac knowledgebase the option 55 feilds would display. All I then needed to do was copy these in the fingerprint and it worked fine. Many thanks for your help again.

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