Rick:
If you only want to allow incoming ssh sessions from that address block, use iptables and insert a rule: -A INPUT -p tcp -m tcp -s 200.100.0.0/16 --sync --dport 22 -j ACCEPT and make sure the last rule is something like: -A INPUT -p tcp -m tcp --tcp-flags SYN,ACK,FIN,RST SYN -j DROP to drop any other connection attempts other than the ones allowed above it.
How does this differ from the hosts.allow & hosts.deny method? Justin:
If you would be able to tell us which ISP you have, you may be able to narrow down the address range even more.
I know about whois.org - so I tried it. I had to delve a bit to get the detailed info, but found the range. There is a CIDR - is that what I want? It's narrowed down to /21.
