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Synology VPN Server

Forward ports 500, 1701, 4500 to server

VPN Server: Enable L2TP/IPSec, confirm Authentication is MS-CHAP v2, and set pre-shared key

IPad/IPhone VPN Client: L2TP w/ secret

Windows VPN Client: L2TP/IPSec with pre-shared key

Windows VPN Adapter Options:

Set VPN adapter Security Tab to Layer 2 Tunneling Protocol with IPSec (L2TP/IPSec)

Set Requires encryption (disconnect if server declines)

Set “Allow these protocols” and enable Microsoft CHAP Version 2 (MS-CHAP v2)

Unless you are currently using IPv6, be sure that your AirPort Extreme is configured to use the “Link-local only” setting for IPv6.

You can set this using the AirPort Utility:

AirPort Utility > Select the Extreme > Edit
Internet > Internet Options > Configure IPv6: Link-local only

On your Mac:

System Preferences > Network > Wi-Fi > Advanced
TCP/IP > Configure IPv6: Link-local only

Find out what is preventing your Mac from going into sleep mode by running the pmset -g assertions command. In the example below, the PreventUserIdleSystemSleep is set to 1, which means the system is being kept from going into sleep mode. The com.apple.ppp.pptp and com.apple.ppp.l2tp are the process that are preventing the system from sleeping. Disabling the VPN server allowed the system to sleep.

echelon:~ dervish$ pmset -g assertions
10/20/13 8:32:17 AM MST
Assertion status system-wide:
PreventUserIdleDisplaySleep 0
PreventSystemSleep 0
PreventUserIdleSystemSleep 1
InternalPreventDisplaySleep 0
ExternalMedia 1
DisableLowPowerBatteryWarnings 0
UserIsActive 0
ApplePushServiceTask 0
BackgroundTask 0

Listed by owning process:
pid 36(powerd): [0x0000000900000249] 17:13:31 ExternalMedia named: “com.apple.powermanagement.externalmediamounted”
pid 67(com.apple.serve): [0x0000000100000137] 25:56:48 PreventUserIdleSystemSleep named: “com.apple.ppp.pptp”
pid 67(com.apple.serve): [0x0000000100000136] 25:56:48 PreventUserIdleSystemSleep named: “com.apple.ppp.l2tp”
pid 8690(httpd): [0x00000001000006dc] 11:54:12 PreventUserIdleSystemSleep named: “com.apple.apache.denysystemsleep”

Error:
“The iPad [device name] could not be restored. This device isn’t eligible for the requested build.”

1. Update to latest version of iTunes.
2. Remove/comment out gs.apple.com entry from /private/etc/hosts.
#74.208.10.249 gs.apple.com
3. Restore device.