[CentOS] CUPS halts when no Internet

Hi.

I have CentOS 6 on a HP ProLiant ML110 G7. We have a cobol invoicing
system that prints to LPD printers on Windows hosts via CUPS.

All works great until the ADSL service goes down. The printers stop
working and the service restart gives a connection error.

What will be happening here and how I can solve it? Our previous
server was on CentOS 5 and worked OK.

Thanks.

--
Juan Pablo De Mola Rodríguez