Reply to post: Re: Time to claw some back

OK, this time it's for real: The last available IPv4 address block has gone

Jamie Jones Silver badge

Re: Time to claw some back

part of the scheme uses an IPv4 /30 block, which basically wastes 3 of the addresses. In reality, a scheme that uses something _like_ PPPoE or some other kind of tunneling protocol would only require 1 IP address in a block of 255 to be a gateway address. The additional bandwidth you might get by having to NOT use a tunneling or PPP-derived protocol (maybe 5%, let's say) would be compensated for by a much lower price. The ISP would be able to sell 3 times (or more) as many fixed IPv4 addresses to customers that need them.

What scheme? I believe you, but I've never seen it myself apart from a few niche (and practical) cases. I hope it's just one ISP, not a general USA 'tang?

Most residential services I know use at least /24 or a /23 for their provisions.

But even if they use that reasoning that it's to avoid needing tunnelling, they are wrong.

My current connection isn't tunnelled any more - no PPPoE. - authorisation is done based on the physical connection - i.e. who is "me" is tied to the physical line (even in my days of adsl with PPPoE I'm pretty sure you couldn't login with someone elses user/password on your line - so the authorisation of PPPoE wasn't the prime purpose of its use.)

At the moment, my single external IP address is sitting on a /20 - I don't have the "local lan traffic" sent to me - the remote router deals with that.

Any connections I do try to make to my "local lan" - the remote router replies to arp requests with it's own MAC (proxy arp) which then acts as a bridge to the remote address.

Upshot, single IP address from ISP. No PPP overhead. No small netblock allocation. No leakage of anyone elses data (more importantly, their dross doesn't needlessly slow my link)

From my routers point of view, it's just a normal machine in a /20 network - sending IP packets "directly" to other users machines "on my lan", and routing to the router for addresses off-lan. The remote end deals with the realities.

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