IPv6 support on Virgin media

Perhaps we should just drop the argument ;P...

It is a function of routing in that (IIRC) each layer should replace the mac and recalculate checksums when passing information to the next point.  So yes, it could be that the data is simply hitting that layer in the switch and the old MAC is removed and (due to routing) the new MAC is put in (so the next hop will know the return unit).  The IETF does not dictate changing the MAC throught the NAT layer, so It does appear that it's done because of routing. At the end of the day, it doesnt matter much because regardless of it being done due to the layer of routing or because of NAT (that is on top of that layer) it happens. But some RFC documents also state things like

"

Responding to ARP requests for the NAT mapped global addresses

with its own MAC address is a must ..... with Basic NAT setup.

"

Again tho....

It doesnt really matter...

The innards of some packets are altered "due to nat"

The IP packet is modified each hop with the MAC and Checksum changed "due to routing"

The packets I was thinking of earlier was encapsulated packets that must retain source MAC.

And as the IETF or RFC database is so huge, many of us go by what we know and have discovered (I applaud anyone who has read all of the documents that would relate to common use).

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Dagger wrote:

 

You keep saying that, but you've yet to back it up with any evidence -- and it doesn't match the reality of what happens.

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Thats so funny, here this is about you:
http://www.neowin.net/forum/topic/1060972-should-we-all-tell-him/page__p__594689238#entry594689238

One again I have no idea what to say to that, so I'll just repeat my previous offer: if there's anything you don't understand in my previous posts, please tell me what it is and I'll try to clarify it for you.

Ok Dagger I will play along with your idea of how what you say “NAT never touches MAC addresses at all” by posting your way of thinking.

192.168.0.2   --------------> 74.125.230.147 > NAT > 24.209.40.22 --------> 74.125.230147
22;11;33;CC;DD;02 > 55;AA;88;33;55;88 > NAT > 22;11;33;CC;DD;02 > 55;88;AA;33;55;88
PC1 MAC-------------------> UBR MAC---------> NAT > PC1 MAC---------------> UBR MAC

192.168.0.3   -------------> 74.125.230.147 > NAT > 24.209.40.22 --------> 74.125.230147
22;11;33;AA;BB;01 > 55;AA;88;33;55;88 > NAT > 22;11;33;AA;BB;01 > 55;88;AA;33;55;88
PC2 MAC-------------------> UBR MAC--------> NAT > PC2 MAC----------------> UBR MAC

Now NAT never touches MAC addresses at all you happy.:smileyhappy:

OK, so the bit you're missing is that MACs are changed, but it's done as a result of routing and not NAT.

Dagger and Legacy,

This is starting to spam this thread with bickering. Please take it up via PM

Thanks, Lisa.

I just wonder what's going to happen to Virgin Media broadband users when a web site appears on the Internet which has _no_ IPv4 address, because there simply is no IPv4 address available to give to the creators of that web site.

It is at that point that we will all need our own IPv6 address.

It seems to me that Virgin have either chosen not to address (sorry about the pun) that future requirement, or don't know how to address it.

I know it's some way off yet, but it will happen.

CSW

You're unlikely to come across a website without IP v4 support in the medium term, as there are plenty of IP addresses to host many, many times the current number of websites and it's realtively easy for websites to share IPs (some SSL sites excepted while we need to worry about visitors using IE on XP).

The problem is the millions of people who want to connect to the internet, and each needs an IP to do so. Perhaps a few if they've got smart phones, tablets etc that they want to connect. Virgin Media have been allocated several million IPs, but they've got millions of customers and they can't easily get more IPs as their customer base grows. There will come a point when they either need to turn away potential customers, or make their customers share IP addresses by putting another layer of NAT in.

That's fine for most services, but sometimes you need to open a particular port on your router, and you won't be able to do that on a shared IP. In this scenario you could either pay extra for your own IP, or use IP v6.