Cannot enable SNC in SAPlogon with alternative IP address in SMLG groups

Question

Hello everyone,
I am looking for someone who has overcome the following situation: 
We run SAP Enterprise on Unix (640 kernel).  The systems have 2 networks - one for internal server communications and one for end-user connections.  This requires that in our production logon group (multiple servers) that we specify the end-user IP address as an alternative IP in SMLG (otherwise SAP returns the internal network IP to the client).
However, when I try to enable SNC in SAPlogon to the production logon group, the "enable SNC" flag is grayed out.  I have also tried to manually configure the entry in saplogon.ini.  This results in a logon balancing module error.  All of this seems to be described in OSS note 913356.  The note is not very clear, but seems to list a corrected kernel level for version 4.6D.  Thinking that this might be true for 640, I updated the kernel to 640 patch 159.  This did not resolve the problem.
I should also state that direct saplogon connections to production with SNC do work.  The problem appears to be in the logon module.
Has anyone else experienced this situation?  Any help would be highly appreciated.
Paul
Basis Admin, Medrad

Answer 1

> Hi Paul,
>
> I would read the note like SNC only being available
> starting with NW2004s (700 kernel).
>
> Regards, Patrick
Saying that "SNC is only available starting with NW2004s" could be missinterpreted. Instead, I think it is better to say that "When using load balancing with SNC, for logon to SAP, and using an alternative IP address only works out-of-box with NW2004s". We have many customers using SNC authentication products with load balancing on releases prior to NW2004s, so this patch must be required only because of the alternative IP address being added to the logon group configuration.
Thanks,
Tim