IPsec/L2TP VPN with OSX client: xl2tpd reports "maximum retries exceeded"
Solution 1:
Figured it out. I'm no expert, so I don't know why this works, but I was able to get a connection by adding the following lines to the conn L2TP-PSK-noNAT section of ipsec.conf:
leftnexthop=%defaultroute rightnexthop=%defaultroute