internet connection problem

I own a late 09 mac pro, 2x2.26 quad core intel xeon running OS 10.6.8. 12GB Ram. My internet service provider is Verizon DSL The mac pro is hard wired to the modem via ethernet cable.
I can get on the internet without a problem but after 5 minutes I loose the connection. Network diagnostics indicate the ethernet connection is ok the remaining indicators are yellow or red. If I reset the modem I get a connection. The modem is about a year old and my macbook pro connected thru airport does not have this problem.
Any helpful advice will be greatly appreciated. This is driving me crazy.

Call Verizon support and have them send you a new modem. Verizon is famous for issuing cheap hardware. I have had to change out my Verizon router twice and cable box once. Also I have had a FIOS module fail that had to be replaced by a service technician.

Good idea. Thanks! Just thought about trying the wired connection with my mac-book and see what happens.

when the macbook pro didn't work on the same cat 5 cable I decided to check the phone line that the modem is connected. Discovered that the jack was wired wrong (reversed polarity) I purchased a simple phone line tester at the local hardware store for about five bucks. I guess the guy that wired it was color blind or something. Also replaced the cat 5 wall jack because it didn't seem to make a good connection. I'm happy to report all's well now and I'm the proud owner of a really cool phone line tester and neat punch-down tool.

Great trouble shooting. Been a good while since I've had to trouble shoot telephone lines and mux boxes. Gave away my punch down tool a while back along with an older line tester.

Anyway, glad to hear things are working for you. Not having to mess with Verizon support is always a pleasure.

Yup! I wasn't looking foreword to that.
Thanks again