RE: CPF8907 on STRPASTHR over AnyNet (criticism of IBM)

[Neil Palmer <NeilP@xxxxxxxxxxx>]

Yes, I found the document you included:

http://www-912.ibm.com/s_dir/slkbase.nsf/1ac66549a21402188625680b0002037e/e05fb0515bc3449686256ce600512c37

I notice in the document you sent it says:
Classification: Public Use

whereas the very useful one Gord sent says:
Classification: Entitled/Advanced

It's REALLY annoying that IBM are still hiding documents like these behind 
a "pay only" front.

...Neil





"Burns, Bryan" <burnsbm@xxxxxxxxxxxxxxxxxxxx> 
Sent by: midrange-l-bounces@xxxxxxxxxxxx
2004/07/08 14:44



To
Midrange Systems Technical Discussion <midrange-l@xxxxxxxxxxxx>
cc

Subject
RE: CPF8907 on STRPASTHR over AnyNet






We had some issues with Anynet sessions timing out due to NAT not 
responding
to keep alives.  The solution per IBM was to create data areas that 
lengthen
the time that the keep alive are sent to 18 hours or so.  This solution
worked for us. Here is a copy of support line document regarding this 
issue:



    Document Number:   29904636
  ____________________________________________________________
  Functional Area:                       Communications-SNA
  SubFunctional Area:               AS/400-to-AS/400 Connectivity
  SubSubFunctional Area:       AnyNet
  ____________________________________________________________
  Product:  Operating System/400 - OS400 COMM BASE/APPN (5769SS1CM); OS400
COMM BASE/APPN (5722SS1CM)
  Release:  V4R1M0; V4R2M0; V4R3M0; V4R4M0; V4R5M0; V5R1M0; V5R2M0

  Classification:       Public Use

  Keywords:            AnyNet, ANYNET, APPCTCP
 ____________________________________________________________
 Document Title:AnyNet Not Supported over Networks Using NAT
 Document Description:
  Per APAR MA18298, AnyNet will most likely fail when used over a network
using Network Address Translation (NAT) in some firewall between the two
AS/400 or iSeries systems.  This is because the MPTN (Multi-Protocol
Transport Network) architecture incorporates the use of Keep-Alive packets
to determine if the connection is still active.  AnyNet uses a combination
Source Port/Destination Port of 397 (MPTN) and another undefined port for
sending TCP data.  The AnyNet Keep-Alive uses UDP (not TCP) and uses port
397 for the source and destination ports.

The following example from a communications trace shows how the source and
destination IP addresses are embedded within the UDP data used by the
AnyNet Keep-Alive packet.  If NAT is being used, it will translate only 
the
addresses included in the IP header of the frame.  It will not make any
change to the embedded data within the UDP datagram.  Therefore, when the
data is read by the MPTN code, it will not respond to the Keep-Alive 
packet
because the program is not aware of a connection to that IP address.
Because it does not respond to the packet, the system generating the
Keep-Alive request believes the connection has been terminated and will
initiate the connection to drop.