I added the credit card gateway half a year ago. It has been working until recently.

What happened was that when a customer confirms an order, zen cart sends info to the credit card gateway, they respond back but fail to postback on my zen cart. The results are the credit card transaction does not show up in the zen cart admin panel, and after customer sees "order is being processed..." a blank screen returns. (The customer winds up with a blank page after paying and wondering if the transaction has gone through.)

I found in another thread talking about port 1129 not being open. I checked and found that my server gateway comcast firewall is off, and my ubuntu firewall is inactive. So there is nothing blocking ports. I went further to enable the ubuntu firewall while allow-ing port 1129. this does not fix any problem. At the same time, this site http://www.yougetsignal.com/tools/open-ports/ still says my 1129 port is closed.

I am unable to get any help from the ubuntu forum and am still unsure if the problem is Linux, or zen cart, or even the modem.

Anybody can help?