Possibly a bit off-topic, but curious how all of you out there segment your networks. Corporate/business users, dependent services, etc. from critical data and/or processes with remote locations thrown in the mix which could be mini-versions of your primary network. There's quite a bit of literature out there on this, so have been considering an approach with zones based on the types of data or processes within them. General thoughts: - "Business Zone" - This would be where workstations live, web browsing occurs, VoIP and authentication services live too. Probably consider this a somewhat "dirty" zone, but I should generally be OK letting anything in this zone talk fairly unfettered to anything else in this zone (for example a business network at my HQ location should be able to talk unfettered to an equivalent network at a remote site). I'd probably have VoIP media servers in this zone, AD, DNS, etc. - Some sort of management zone(z) - Maybe accessible only via jump host -- this zone gives "control" access into key resources (most likely IT resouces like network devices, storage devices, etc.). Should have sound logging/auditing here to establish access patterns outsid the norm and perhaps multi-factor authentication (and of course FW's). - Secure Zone(s) - Important data sets or services can be isolated from untrusted zones here. May need separate services (DNS, AD, etc.) - I should think carefully about where I stick stateful FW's -- especially on my internal networks. Risk of DoS'ing myself is high. Presumably I should never allow *outbound* connectivity from a more secure zone to a less secure zone, and inbound connectivity should be carefully monitored for unusual access patterns. Perhaps some of you have some fairly simple rules of thumb that could be built off of? I'm especially interested to hear how VoIP/RTP traffic is handled between subnets/remote sites within a "Business Zone". I'm loathe to put a FW between these segments as it will put VoIP performance at risk (maybe QoS on FW's can be pretty good), but maybe some sort of passive monitoring would make sense. (Yes, I've also read the famous thread on stateful firewalls[1]). Thanks! [1] http://markmail.org/thread/fvordsbnuc74fuu2#query:+page:1+mid:fvordsbnuc74fu...