When VPNs work, they can be great; when they don't, they can be a menace to troubleshoot. This section visits several specific problems that you may encounter when using VPN with the iPad or iPhone (or trying to).
iPad VPN Works the First Time but Fails After That
On an iPad, connecting to a Cisco VPN with IPSec works fine the first time you use it after setting up the connection. Thereafter, it fails. At this writing, the only solution is to delete the connection and set it up again.
iPad Can't Connect Through UDP, Only TCP
The iPad's built-in Cisco VPN client only uses TCP, not UDP-so if your VPN uses UDP, the iPad is going to be straight out of luck.
The best fix-okay, you've guessed it-is to open a TCP port on the remote access server to keep the iPad happy.
iPad and iPhone Don't Support IPSec Tunnel with Older PIX Models
If you're having trouble getting the iPad and iPhone to connect via IPSec VPN to a Cisco VPN concentrator, double-check that your concentrator supports the iPad and iPhone as VPN clients.
Cisco routers running Cisco IOS Release 12.4(15)T and later, and Cisco ASA 5500 Security Appliances and PIX Firewalls with Release 7.2.x (or, better, 8.0.x) or later, do support the iPad and iPhone as VPN clients. The VPN 3000 Series concentrators don't; neither do the Cisco IOS VPN routers.
iPad Fails to Save Password for Cisco VPN
If you find that the iPad fails to save the password for a Cisco VPN (so that the user has to enter the password on each connection), the problem may be that the VPN concentrator is set to not permit the clients to store the password. To solve this problem, use the password-storage enable command on the concentrator to permit the clients to store their passwords.
In this tutorial:
- iPad and iPhone Users Remote Access to the Network
- Planning How to Connect the iPad and iPhone to Your VPN
- Setting Up the iPad and iPhone to Connect to the VPN
- Specifying the Authentication for an L2TP VPN
- Specifying the Authentication for a PPTP VPN
- Specifying the Authentication for an IPSec VPN
- Specifying the Authentication for a Cisco AnyConnect VPN
- Enabling VPN On Demand for VPN Connections
- Setting Up a VPN Connection Manually
- Specifying the Authentication for an L2TP VPN Connection
- Specifying the Authentication for an IPSec VPN Connection
- Using a VPN
- Troubleshooting VPNs
- Remote Control of Computers on Your Network