Talk:Classful network

message: I'm pretty sure 127.0.0.1 is the normal loopback address.
Any ideas on resolving this? --217.204.169.167 15:56, 14 Mar 2004 (UTC)
thread_title: Loopback

message: Don't be, it is the American Government you need to worry about.[Anonymous] —Preceding unsigned comment added by 201.19.199.6 (talk • contribs) 
:I suggest you become a bit more familiar with the history of the Internet. In point of fact, the military proper had relatively little to do with the original development of the ARPANET and Internet, but provided funding to academic research organizations, including European and Asian organizations. I suggest you look at the rules at which IP addresses were originally allocated, and the present roles of the continental Regional Internet Registries, such as RIPE-NCC, APNIC, LACNIC, AfriNIC, and yes, ARIN. You seem to have an idea that there is some American organization that can give and take IP addresses away. It's not. Certain companies and universities, involved in research early on, did get large blocks. Some, such as Stanford University, returned their original large space, but at their own initiative. One of the reasons the allocation was wasteful is a point of this article: classful addressing is inefficient, but that's how initial allocations were made. Techniques such as Network Address Translation didn't exist for the ARPANET.
:There are perfectly valid technical reasons to have blocks of registered addresses that are not accessible in the public Internet, such as for international telecommunications and financial organizations that are sufficiently large to need a block they can allocate to new members, without fear of duplication.
:Classless Inter-Domain Routing (CIDR) enormously increased address allocation efficiency. In any event, whether or not organizations give up IPv4 address space, there are good reasons to go, systematically, to IPv6 addressing. The obsolescence of the IPv4 address space is not merely a matter of exhaustion, but of issues such as aggregation. Hcberkowitz 22:44, 25 June 2007 (UTC)
replies: text: Suggesting that some orgs should give up addresses is not the same as saying that IPv6 is a bad idea. If the exhaustion of addresses is occuring more rapidly than IPv6 testing and deployment, then adjusting some of the wildly inefficient allocations seems like a natural way to bridge the gap.  —Preceding unsigned comment added by 204.87.16.4 (talk) 10:43, 17 March 2011 (UTC)
thread_title:  I'm afraid of Americans 

message: Normally I'd just do a little gnoming on this, but I'm not sure I understand the subject sufficiently to be certain I'm not mistaken...
"defined a different size or type (unicast or multicast) of the network."
Shouldn't "the" be removed from that sentence, or else the "defined a different size or type" be changed to "defined the size or type"?  —Preceding unsigned comment added by Dr.queso (talk • contribs) 04:21, 30 June 2010 (UTC)
replies: text: I agree the wording of the lead was somewhat confusing, and I have reworded it. Part of that was to change the tense from "defined" to "defines" because although classful networks are no longer used on the Internet, and indeed are probably extremely rare if not non-existent, there is nothing to stop someone setting up a classful network, so strictly past tense is clumsy and inaccurate. Johnuniq (talk) 07:20, 30 June 2010 (UTC)
thread_title: Lead

message: As I study for my CCNA exam, after many years of doing this sort of stuff, I am repeatedly bumping on the fact that Cisco Certifications still care about classful addressing, and I just can NOT figure out why. Sure, it's an interesting historical note, but WHY do they insist on you learning about it? It seems a worthwhile note to add here, if anyone has any clue.
Jbsegal (talk) 17:50, 27 September 2020 (UTC)
thread_title: Why does Cisco still care?

message: the most significant eight bits of the 32-bit IPv4 address was the network number field
As a consequence of this architecture, the address space supported only a low number (254) of independent networks.
If I have eight bits in the network number field, I'd expect to get 256 possible networks out of that. Were there two special network numbers that couldn't be assigned to networks? Similar to the network ID and broadcast address in the host part of IPv4? Mb720 (talk) 00:34, 16 December 2023 (UTC)
thread_title:  ARPANET network number