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> possibly in a backward compatible way Pre-IPv6 all IP code had 32 bits reserved for addresses. For more addresses, you would need >32 bits. How do you squee

> possibly in a backward compatible way Pre-IPv6 all IP code had 32 bits reserved for addresses. For more addresses, you would need >32 bits. How do you squeeze >32 bits of data into 32 bit data structures? You would need to touch every bit of IP code out there to expand the corresponding address filed (e.g., in a struct in_addr)—which is what had to be done for IPv6.

patentatt 5y ago
I'd argue that that's in essence what NAT (especially CGNAT) does by abusing the 16 bit port number: extend the 32-bit assessing space to ~48 bits. And it pretty much works just fine for many many use cases.
- tinus_hn 5y ago
  Because NAT is really pervasive basically only the use cases that work with it survived.
  - throw0101a 5y ago
    * https://en.wikipedia.org/wiki/Survivorship_bias https://en.wikipedia.org/wiki/Survivorship_bias
- throw0101a 5y ago
  Because a whole suite of protocols had to be invented: * https://en.wikipedia.org/wiki/STUN https://en.wikipedia.org/wiki/STUN * https://en.wikipedia.org/wiki/Traversal_Using_Relays_around_NAT https://en.wikipedia.org/wiki/Traversal_Using_Relays_around_... * https://en.wikipedia.org/wiki/Interactive_Connectivity_Establishment https://en.wikipedia.org/wiki/Interactive_Connectivity_Estab... See also "NAT Issues when playing games": * https://support.plume.com/hc/en-us/articles/360035745134-NAT-Issues-when-playing-games- https://support.plume.com/hc/en-us/articles/360035745134-NAT... Certainly we'd need hole punching protocols (UPnP/PCP) because IPv6 firewalls would be default deny on incoming connections, but the addressing issue introduces a bunch of things on top of that. The fact that these kludges are considered 'normal' and/or 'okay' is kind of sad. And how do you hole punch through CGNAT? (AFAIK there is no way.) Everything is being crammed into HTTP/QUIC/whatever because of all of these limitations: what applications could have been designed better if bits flowed more freely? (SCTP and DCCP died because of limited middleware network boxes.)
  - GoblinSlayer 5y ago
    As the TRUN article says, only the symmetric NAT is impregnable, you can punch holes through other types on NAT.

patentatt 5y ago

I'd argue that that's in essence what NAT (especially CGNAT) does by abusing the 16 bit port number: extend the 32-bit assessing space to ~48 bits. And it pretty much works just fine for many many use cases.

tinus_hn 5y ago
Because NAT is really pervasive basically only the use cases that work with it survived.
- throw0101a 5y ago
  * https://en.wikipedia.org/wiki/Survivorship_bias https://en.wikipedia.org/wiki/Survivorship_bias
throw0101a 5y ago
Because a whole suite of protocols had to be invented: * https://en.wikipedia.org/wiki/STUN https://en.wikipedia.org/wiki/STUN * https://en.wikipedia.org/wiki/Traversal_Using_Relays_around_NAT https://en.wikipedia.org/wiki/Traversal_Using_Relays_around_... * https://en.wikipedia.org/wiki/Interactive_Connectivity_Establishment https://en.wikipedia.org/wiki/Interactive_Connectivity_Estab... See also "NAT Issues when playing games": * https://support.plume.com/hc/en-us/articles/360035745134-NAT-Issues-when-playing-games- https://support.plume.com/hc/en-us/articles/360035745134-NAT... Certainly we'd need hole punching protocols (UPnP/PCP) because IPv6 firewalls would be default deny on incoming connections, but the addressing issue introduces a bunch of things on top of that. The fact that these kludges are considered 'normal' and/or 'okay' is kind of sad. And how do you hole punch through CGNAT? (AFAIK there is no way.) Everything is being crammed into HTTP/QUIC/whatever because of all of these limitations: what applications could have been designed better if bits flowed more freely? (SCTP and DCCP died because of limited middleware network boxes.)
- GoblinSlayer 5y ago
  As the TRUN article says, only the symmetric NAT is impregnable, you can punch holes through other types on NAT.