tn3270 work through VPN?

[dip...@hotmail.com]

Hi,

I recently replaced a bt kilostream link between two remote sites with
a couple of broadband/netpilot vpn boxes (using ipsec cipe). The
company uses a tn3270 application at their headquarters which works
fine through the old kilostream link yet for some reason fails to work
through the vpn tunnel (all of their other apps work fine).

I've checked all of the networking stuff, paths, ensured no packets are
being dropped/firewall issues etc but am left totally foxed by this. I
can ping the server its meant to connect to, and the tn3270 emulation
software never actually gives me an error message, just a black screen
where I would be expected login screen text of some sort.

I've used ethereal to have a look at the network packets being sent to
and fro. I can see that communications on the required ports are being
made. On a successfully working connection using the old kilostream
there are about 16 packets sent back and forth and then the login text
appears, but using the vpn, the communication seems to stop at about 13
packets and all I get is a blank screen no errors. On clicking
disconnect from the emulation software it actually says some text like,
connection to the server on port 9000 was successful etc.

The vpn is rock solid and never drops (there are other apps which would
show problems if this was the case).

Does anyone have any experience of using a tn3270 session over a vpn?
(I'm running out of things to check...)

Thanks

Asim

[robert...@yahoo.com]

You're probably coming in on different IP addresses than before. The
TN3270 server (either on the mainframe or in an external device) may be
applying some filtering. For example, in TCP/IP for MVS you might have
a IPGROUP defining your old range of network addresses, which may need
to be updated.

[howard...@cusys.edu]

With a VPN, we used our old 3270 emulator - but our new one is secure
and doesn't need the VPN, now we use BlueZone at work and at home.

We can still use our VPN to log into our work computers from home, or
we can use BlueZone from our home computers.