On Sat, Oct 15, 2011 at 01:32:47AM +1030, Tim wrote: > Out of the various IP ranges [1] that are available for private use, > because they are not, and will not, be used as public IPs on the > internet, ... Very specifically, look up RFC1918, where these ranges were defined. > It's common practice to use an address ending with 254 for routers and > gateway, but it's purely customary. Actually, in my experience it's much more customary to use the .1 adress as the main gateway in the network, especially for Class 'C' networks. I really only started seeing .254 when some of the manufacturers of retail router/firewalls picked it. But, as you say, it's a matter of convention. Probably the most important item to pick up on is to put the main gateway at one end or the other of the subnet address range. > As for how to allocate IPs within a LAN, that's up to you. Some people > have ... It is extremely useful to have conventions for IP address assignment, since you, as the administrator, can look at an address and *know* what that piece of equipment should be, or can *know* where to start assigning static IP addresses if necessary (e.g., for printers, VOIP phone systems, etc.) A common convention I've used for (literally) decades now is: Low addresses: Network Equipment (gateway, routers, terminal servers, etc.) Next range: Servers Next range: Printers & end-user equipment w/static addresses DHCP Range Top Addresses: VPN addresses, experimental/temporary equipment Just what these values are depends on how big your subnet is. For instance, most people use what we called a Class 'C' subnet--netmask is 24 bits (255.255.255.0)--allowing a max of 254 devices; let's use 192.168.100.0 as an example subnet: 192.168.100.0 - Entire Network 192.168.100.1-254 - Usable device range 192.168.100.255 - Broadcast Address For this small network, a usable convention would be: 192.168.100.1-9 - Network Equipment. Gateway at 192.168.100.1 192.168.100.10-20 - Servers 192.168.100.21-99 - Printers & End-User Equipment w/static addresses 192.168.100.100-199 - DHCP-assigned addresses 192.168.100.200-254 - VPN addresses, experimental/temporary equipment As a further convention, if you're using a VPN scheme that requires address assignment, start from 254 and work down; that lets you know that if you want to temporarily assign ad-hoc static addresses, you can start at 200 and work your way up. Obviously, you can shift the boundaries to meet your local needs; and if any of these ranges are too small, you can pick one of the Class 'A' or Class 'B' (yeah, I know, old terms) address/netmask combinations. Cheers, -- Dave Ihnat dihnat@xxxxxxxxxx -- users mailing list users@xxxxxxxxxxxxxxxxxxxxxxx To unsubscribe or change subscription options: https://admin.fedoraproject.org/mailman/listinfo/users Guidelines: http://fedoraproject.org/wiki/Mailing_list_guidelines
