RE: V5R3 iSeries Access ports needed for VPN from home

Have you tried CWBPING instead of PING?  CWBPING does the same thing as
the iSeries Access "Verify Connection" - it tries to talk to each of the
iSeries Access services and reports what worked & what failed. 

Sample:

C:\Windows>cwbping xxx.xxx.xxx.xxx

IBM iSeries Access for Windows
Version 5  Release 3  Level 0
Connection Verification Program
(C) Copyright IBM Corporation and Others 1984, 2003.  All rights
reserved.
U.S. Government Users Restricted Rights - Use, duplication or disclosure
  restricted by GSA ADP Schedule Contract with IBM Corp.
Licensed Materials - Property of IBM

To cancel the CWBPING request, press CTRL-C or CTRL-BREAK
I - Verifying connection to system xxx.xxx.xxx.xxx...
I - Successfully connected to server application: Central Client
I - Successfully connected to server application: Network File
I - Successfully connected to server application: Network Print
I - Successfully connected to server application: Data Access
I - Successfully connected to server application: Data Queues
I - Successfully connected to server application: Remote Command
I - Successfully connected to server application: Security
I - Successfully connected to server application: DDM
I - Successfully connected to server application: Telnet
I - Connection verified to system xxx.xxx.xxx.xxx