[cobalt-users] What does the subnet mask on a PTR record mean?

["Juergen Weber" <Juergen.Weber@xxxxxxxxxxxxxxxxxx>]

Hi All,

we have a class C net and are providing IP based webhosting. That means,
every domain has its own IP address. Now we want to create the correct
PTR records for all IPs and domains. But how? The RAQ 550 GUI asks me to
provide the IP address, the subnet mask, the domain and host name. Of
course the system needs the IP, the host and the domain name. 

But why do I have to insert a subnet mask? And which subnet mask is
correct? 

Thanks
Juergen