I am building a new VPN implementation for a customer using a Cisco ASA 5550 and a NAC 3350 appliance. Due to the availability of switch ports, my customer is inquiring to see if the ASA can be cabled directly to the untrust interface on the CAS. I plan to implement the CAS in VGW mode.
If this is possible, how would the VLAN Mapping work in VGW with this implementation? Do I need to configure a trunk on the ASA to pass the VLAN tags to the CAS to MAP the untrust to the trusted VLAN?
I do agree having this configuration will limit them on redundancy and most likely we will go with a switched approach. If we have both the untrusted and the trust interfaces connected to the same switch with an edge deployment do I need VLAN mapping configured or can the NAC bridge the two vlans without the mapping? I suspect without mapping we would introduce loops.
Based on the examples I've seen on cisco.com with VPN concentrators, VLAN mapping is used with 4 vlans. 2 are native vlans and a untrusted and an untrusted VLAN - this was the same approach I was going to use. Also note that the ASA will not be used for Internet access, only VPN. See below image - the ASA would connect to the switch as an access port on VLAN3. The customers internal lan would connect to VLAN2.
Table of ContentsIntroductionVersion HistoryPossible Future
UpdatesDocuments PurposeNAT Operation in ASA 8.3+ SectionsRule Types
Network Object NATTwice NAT / Manual NATRule Types used per SectionNAT
Types used with Twice NAT / Manual NAT and Network Obje...
Table of Contents Introduction:This document describes details on how
NAT-T works. Background: ESP encrypts all critical information,
encapsulating the entire inner TCP/UDP datagram within an ESP header.
ESP is an IP protocol in the same sense that TCP an...