ejb to ejb

I am putting this question which is specifically related to weblogic
I have never used any other app server
Well one of our products eGain Mail in running on weblogic 5.1 service pack 8
and another product eGain Knowledge runs on 5.1 sp 9
Both of the products uses ejbs extensively
Now when i try to connect from mail ejbs to knowledge ejbs
It gives me communication exception
One reason may be that knowledge server is in US and Mail server on my machine in India
My machine is NT and US server is solaris
Since we failed to connect, the US guys put the knowledge server also on sp8 since weblogic support team said that u need THE SAME SERVICE PACK
so the we tried ejbs from sp8 to sp8
but still i am getting the same communication exception
Can anybody please tell me if you have succesfully used ejbs communicating with ejbs. If yes which sp

I am really eager to know this other wise our integration of two products has to suffer

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"Sun Certified Java Programmer"
KS
"Failing to plan is like plannig to fail!"

Communication between EJBs is done over the Internet ?
Yes?, so you need to know that EJBs use IIOP protocol to communicate (since EJB1.1). This protocol (TCP/535) is not recognized by the firewalls. So U need to ask to FireWalls Administrator or Network Admin to open the port 535 on TCP in order to let IIOP going through.
Be careful, because it's a BIG security hole, IIOP is a "rich" protocol , a hacker could execute easily execute methods on yours distributed objets (EJB); and if U don't want to open firewall, you can choose to make HTTP tunneling for the IIOP. In this case ... U're lucky

because all this stuff is implemented in WLS ... just have a look in the docs by searching HTTP tunneling
The main problem of this manner of doing is that is not very performant (it seems to be a gaz machine to wrap IIOP into HTTP) but U have no choice.
for your information, OMG , that is the founder of IIOP (with CORBA) works on a way to specify IIOP in order to make IIOP suitable for Firewalls.

Sorry
forgot to mention these things
I tried using T3,HTTP and IIOP
Not sure how exactly tunneling is used
We do not have proxy server/ firewall
There is a leased line between US and India office
If service packs are same T3 should have worked