On Wednesday, 05/26/2010 at 10:21 EDT, Hans Rempel 
<[email protected]> wrote:
> I?m using hummingbird(new version 13) with SSL support (selfsigned 
> certificate). I?m failing on Linemode connection which means my 
max_cmd_len is 
> 0 within my scexit exec. I?m on z/VM 5.4 and CMS SSL services 390 engine 
with 
> VMSECURE active. 
> 
> I switched the same hummingbird session IP address to my LINUX VM 
system, same 
> configuration, and connected without a problem using SSL so I don?t 
think it is 
> the Hummingbird session definitions. No VMSECURE running in the Linux 
VM. 

Linemode telnet is securable with SSL using application-transparent TLS 
(AT-TLS), which VM sometimes refers to as "static SSL".  In this scenario 
you configure port 23 (for example) with the SECURE option in the PORT 
list.  SSL/TLS sessions must be established before any protocol-specific 
data flows on the connection (a la https).

There are no RFCs (draft or otherwise) that I'm aware of that provide for 
negotiated SSL for linemode telnet.  There *is* RFC 2946 for general 
telnet encryption, but it doesn't use SSL/TLS and VM doesn't support it. 
Perhaps Linux and Hummingbird support it?

> Don?t think VMSECURE is the problem but I thought I mention it.

The ESMs are not involved in SSL.

> Has anyone ran into this problem or has any ideas why TCPIP sets the 
connection 
> with max_cmd_len of 0?

The purpose of the command line is to allow you to issue DIAL commands for 
3270 sessions.  Since linemode terminals can't DIAL, there's no provision 
in the exit to let you issue a command.

Alan Altmark
z/VM Development
IBM Endicott

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