I set up a Optwre PPTP VPN server on my Asus RT-N16 router per "Configuring a PPTP VPN". The Asus (10.2.0.1) is inside an Apple Time Capsule (10.0.1.1). After hunting down several corrections to the VPN setup, I've gotten as far as getting packets from the iPhone 4 client (currently at 10.0.1.6) to show up in the router logs when I try to connect:
Apr 1 18:10:28 JJR2 user.warn kernel: DROP IN=vlan2 OUT= MAC=<> SRC=10.0.1.6 DST=10.2.0.1 LEN=64 TOS=0x00 PREC=0x00 TTL=64 ID=12162 DF PROTO=TCP SPT=57903 DPT=1723 WINDOW=65535 RES=0x00 SYN URGP=0 OPT <>
But the client packets are dropped, and the client eventually fails to connect with a "server did not respond" message.
Also, I can successfully restart the PopTop server, but the log shows the following error message each time:
Apr 1 18:09:48 JJR2 daemon.err pptpd: MGR: Bad IP address (10.2.0.256) in config file!