Based on your budget, you can use 800 or any other supported router. As you have many options here, I suggest you speak to you cisco account rep/authorised reseller. They should be able to provide you with better solution.Just to share with you, We have ASA5510 at HQ as eayvpn server and home users get ASA5510 with base license. Both work PC and phone connect back to our network using ezvpn tunnel. This works great.
I never implemented myself but remember seeing postings in the forum with ref to 800 being VPN server. Never worked on SR520 as wll but if Iam correct, Cisco announced end of life/support dates for SR520. I wouldn't invest in the gear with EOL announced.
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...