I know this post is a year old but I have recently had to revisit this so thought I would post back my results.
What I found was that the commands 'crypto logging session' and 'crypto logging ezvpn', were not working. My understanding is that my AnyConnect system is using SSL VPN, not IPSEC, hence that is why it was not working.
I did a bit of googling and couldn't find any logging options for SSL VPN/Anyconnect. There were plenty of debug options though.
After turning on debugging for aaa using the following command, 'debug webvpn aaa', the messages below were generated.
WV-AAA: AAA authentication request sent for user: "demo" WV-AAA: AAA Authentication Passed! WV-AAA: AAA authentication request sent for user: "demo" WV-AAA: AAA Authentication Failed!
This worked great, but since it was using the debug option, I would loose the logging after a reload.
Then I came across these commands
login on-failure log login on-success log
These are more of a global option, that log not just success/failures for Webvpn but also things like SSH, Telnet sessions etc.
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...