Looking at all possible subnet masks, you get:
subnet mask | # subnets | # hosts/subnet | total # hosts | usage -------------+------------+----------------+---------------+------ 1:7 | not allowed| | | 2:6 | 2 | 62 | 124 | 49 % 3:5 | 6 | 30 | 180 | 71 % 4:4 | 14 | 14 | 196 | 77 % 5:3 | 30 | 6 | 180 | 71 % 6:2 | 62 | 2 | 124 | 49 % 7:1 | not allowed| | |
Just one probably silly question - why should the subnet mask 1:7 not be allowed? If I get it right, you speak of netmask like 255.255.255.128. Which should let you have two subnets of 126 hosts each. Daniel