Silent Post connection test tool?

[alternapop]

Is there a connection test tool for checking if authorize.net servers are able to make a connection back to our configured Silent Post url?  Even a basic telnet type test would be ok.

I can run a successful test in my sandbox account but can't find a way to see if authorize.net servers are able to communicate back to our server.

[alternapop]

I'm still looking for a way to test if authorize.net servers are able to connect to my web server. Is there not a simple way to test this without us converting over our test/production environments locally?

I see that the Silent Post IPs are supposedly these:

198.241.168.60 
198.241.162.104

198.241.206.38

198.241.207.38

However, this page only mentions 2 of them. I'm assuming these 4 are all that are needed but it would quite helpful if there was a way to test it. Otherwise we need to coordinate a meeting with the software vendor, network security, etc. It's much more of a hassle.