Skip to main content

VPN gateway setup for Android 5, iOS 9, and Mac OS X 10.10

I recently configured an IKEv1 L2TP/IPSec VPN for a customer. They needed support for a mix of Android 5, iOS 9, and Mac OS X 10.10 clients. During testing and going through debug logs on the VPN gateway, I found that these devices announce support for several authentication hashes, and encryption protocols:
OSauthenticationencryption
Android 5SHA256-128, SHA1-96, MD5-96AES256, AES128, 3DES, DES
iOS 9SHA1-96, MD5-96AES256, AES128, 3DES
Mac OS X 10.10SHA1-96, MD5-96AES256, AES128, 3DES

The working configurations I found were:
authenticationencryption
SHA13DES
SHA1AES128
SHA1AES256

and I settled on the last combo as AES256 is the strongest CBC from that list.

PS for DH key exchange, only so-called Group 2 1024modp was in the list on all three devices, so there was no other choice available, and no further testing was done.
PS2 I tried SHA256 authentication with the Android device, but no successful connection could be set up with the VPN gateway. It looks like there was some kind of incompatibility between the SHA256 implementations on both devices. As the Apple devices didn't announce support for SHA256, there was no reason to debug that in this environment.
PS3 Some of the acronyms encountered during these tests: IKE, HMAC, PRF, CBC

Comments

Bert de Bruijn said…
An additional comment: I configured "main mode", not "aggressive mode" because I've read that could allow dictionary attacks. I tried to get PFS (Perfect Forward Secrecy) to work, but didn't succeed. The Zywall VPN gateway config allows for different DH PFS algoritms, but even DH2, which should correspond to the 1024modp, didn't work.
4/12/15 10:55
Post a Comment

Popular posts from this blog

Volkswagen UHV bluetooth touch adapter & its problems

My Volkswagen car has the "universal cellphone preparation" UHV built-in. This is the main part of a car kit, but requires an additional adapter for connecting to a cellphone. At first, I was using an adapter for my good old Nokia 6310, even after I changed to the Nokia E71. Connecting was easy: pair the phone with the "VW UHV" bluetooth entity, and done. This has the phone connected to the car kit at all times, so even non-call-related functions use the car audio system (e.g. voice recognition). But progress will have its way, no matter what happens. So in comes the "bluetooth touch adapter". Instead of a phone-specific adapter, this is a small touchscreen device that slots into the UHV dashboard mount. Connecting a phone is very different now: the Bluetooth Touch Adapter connects to the "VW UHV" device via bluetooth the phone connects to "Touch Adapter" device, also via bluetooth The device doesn't allow step 2 if step 1 didn'...
12 comments
Read more

Reset lost root password on vSphere ESXi 6.7

VMware's solution to a lost or forgotten root password for ESXi is simple: go to  https://kb.vmware.com/s/article/1317898?lang=en_US  and you'll find that "Reinstalling the ESXi host is the only supported way to reset a password on ESXi". If your host is still connected to vCenter, you may be able to use Host Profiles to reset the root password, or alternatively you can join ESXi in Active Directory via vCenter, and log in with a user in the "ESX Admins" AD group. If your host is no longer connected to vCenter, those options are closed. Can you avoid reinstallation? Fortunately, you can. You will need to reset and reboot your ESXi though. If you're ready for an unsupported deep dive into the bowels of ESXi, follow these steps: Create a bootable Linux USB-drive (or something else you can boot your server with). I used a CentOS 7 installation USB-drive that I could use to boot into rescue mode. Reset your ESXi and boot from the Linux medium. Ident...
Post a Comment
Read more

GEM WS2 MIDI System Exclusive structure and checksums

MIDI is the standard for communication between electronic music instruments like keyboards and synthesizers. And computers! While tinkering with an old floppy-less GEM WS2 keyboard, I wanted to figure out the structure of their System Exclusive memory dumps. SysEx is the vendor-specific (and non-standard) part of MIDI. Vendors can use it for real-time instructions (changing a sound parameter in real-time) and for non-real-time instructions (sending or loading a configuration, sample set, etc.). In the GEM WS2, there's two ways of saving the memory (voices, globals, styles and songs): in .ALL files on floppy, and via MIDI SysEx. The .ALL files are binary files, 60415 bytes long. The only recognizable parts are the ASCII encoded voice and global names. The SysEx dumps are 73691 bytes long. As always in MIDI, only command start (and end) bytes have MSB 1, and all data bytes have MSB 0. The data is spread out over 576 SysEx packets, preceded by one SysEx packet with header informat...
23 comments
Read more