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asa DMZ help



I need to incorporate three DMZ networks


on the same switch another 4 server vlans which are fine where they are 


I have a 5512 connected to a layer 3 switch via a routed port


how can this be done ? 





I guess one of the typical solutions would be to configure the server port to their own Vlan on the switch and configure a Trunk interface between the switch and the ASA. And in this case there would naturally be no L3 interface for these Vlans on the L3 switch or if there is it would not be the gateway for the actual subnets (gateway on the ASA)


As your current link between the ASA and the L3 switch is a routed link you could either configure a new physical link between the switch and the ASA or modify the current link to a Trunk. If you configured the current link as Trunk then naturally every subnets gateway should be moved to the ASA and the switch would mainly act a normal L2 switch.


Naturally if you want to keep the switch L3 for all the subnets and still route the traffic through the ASA then you could check if the switch supports VRF Lite (or whatever the official term is) and

  • Configure a VRF for each different network segment
    • Separate VRFs for the required DMZs
    • Single one for the LANs unless you want to separate the LAN traffic also (if you even have multiple LAN subnets)
    • and so on


Using the VRFs would separate the routing of the subnets configured under the Vlan interfaces and you could route all traffic through the ASA. The link between the ASA could be Trunk in this case. Naturally if there is need you could use a couple of physical interfaces on ASA/Switch and configure a Port-channel between the ASA and the L3 switch if you feel that one 1Gbps link is not enough. Though I guess the ASA models throughput was pretty close to 1Gbps anyway.


- Jouni




could I create seperate vlans for DMZ

create seperate subnet for dmz related traffic

secure traffic between dmz network and managment network using ACL's on the switch 


I have seen VRF lite 

how would the config look like if I decided with your last option . I have 3850 for L3 

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