I am attemting to establish a VPN between a RB450G and RV042.
I have a current VPN connection with 2 RV042s and need to replace one of them.

Full /24 subnets on both ends :: IKE with Preshare key - 3DES / MD5

I followed a sample at http://gregsowell.com/?p=787 but I cannot establish a connection ... Any help will be appreciated.

EDITED!!

IIRC, you have to set IPSec Policy, Action, Level to "unique" to make it work

Anything in the logs?
Go to System, logging and add a rule for "ipsec, !packet" to get some info and add "debug" it you need extremely verbose logs

I found the issue: It was in the DH Group. The Linksys shows Group 1, 2, 5. The Mikrotik shows modp1024 as the default and modp768 is at the bottom of the stack. Once it dawned on me the corolation of the difference in the two I corrected the problem and my VPN is up.

You need to go to the bottom of this page to catch the issue: http://wiki.mikrotik.com/wiki/IPSec_VPN ... ys_BEFVP41

I also found this to be of use:http://wiki.mikrotik.com/wiki/Manual:IP ... man_Groups

I hope that this helps someone else in the future.

FYI - The RV042 also supports AES encryption as does RouterOS - and AES will typically run faster than 3DES.

Which one of the 3? 128, 192, 256

Those numbers refer to the key length. If 128 bits is sufficient for your purpose (likely) then it uses least resources.

Thanks