Posts in Security

Solaris Entropy statistics

securityNov 3, 2004 1 min read

I had an email exhange with Andy Tucker regarding Solaris 9 entropy pools and found out that entropy statistics are available through mdb's (modular debugger) "rnd_stats" dcmd: With Solaris 10, you can use the "swrand_stats" and "rnd_stats" dcmds to get entropy statistics: I wish there was a way to tell if an application blocked because of a depleted pool in Solaris 9 (dtrace may solve this problem in Solaris 10).

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OpenBSD PF Filtering traffic by Operating System

securityOct 27, 2004 1 min

I was reading through the PF manual, and came across a section on filtering traffic with Passive Operating System Fingerprinting. PF contains dozens of Operating System fingerprints. The full list of fingerprints can be printed with the pfctl utility: Or with one of the available UNIX pagers: Using the fingerprints listed here, we can filter inbound connections by IP address, TCP/UDP ports, and Operating System: This example will allow OpenBSD systems with an IP address in the 192.168.1.0/24 network to ssh to any machine on our network. This has some interesting uses.

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