Re: TCP/IP and programming connectivity problem (routing table question)

[Larry Bolhuis <lbolhuis@xxxxxxxxxx>]

Darren,

  You are right on.  Internet RFCs stipulate that a host should not 
respond to traffic from a host to which it does not have a route either 
static (entered manually) or learned. OS/400 follows the RFCs as closely 
as possible IP Routing is no exception. Some other 'wannabe' OSs will 
simply respond back through the router (gateway) from which the packet 
originated but this is a security exposure.

  For your VPN solution you will need to add a route to the subnet the 
clients are being assigned, typically this is to the firewall or  other 
VPN concentrator.  On the other site you will need to add a route to the 
server running the Delphi application.

  - Larry

Darren McBride wrote:

> Folks,
>
> I didn't know which list would be more appropriate, so I have sent it to
> both above. Apologies if one or the other is not suitable. 
>
> My problem is that I have written a set of RPG ILE service programs on the
> AS/400 and a Delphi Server application on the PC. At one client site the
> AS/400 can communicate perfectly with the Delphi TCP/IP server when I am on
> site. When I connect over a VPN, I get a different network address (which
> does not appear in the TCP/IP routing table on the AS/400) and the
> communication no longer works.
>
> I am now trying to setup the same programs on another site, and the service
> program to PC communication is acting the same (ie. no traffic to the PC).
>
> My question is, are routing table entries on the AS/400 necessary to
> communicate with particular PC network address ranges (kinda like acting
> like an outbound firewall).
>
> Am I making any sense at all ?
>
> Thanks in advance,
> Darren McBride

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