Apparently YP is designed for 10.000 entries (=10.000 users). The Linux kernel could handle 65.000 users YP will be slow, but it could only give problems with the underlying libgdbm, YP can handle 32bit UIDs, the kernel only 16bit UIDs. So at first we get a problem with the linux kernel. Currently we are splitting our nis servers across several isolated networks but this is certainly not the way to have to continue for ever.