alt Hacker News> The IPv4+ could pass through a router that doesn't know about it
It couldn't do that reliably. We don't have any flags left for that that. Options are not safe. We've got one reserved flag which is anyways set to 0, so that's not safe either.
> The IPv4+ could pass through a router that doesn't know about it
It couldn't do that reliably. We don't have any flags left for that that. Options are not safe. We've got one reserved flag which is anyways set to 0, so that's not safe either.
> We don't have any flags left for that that.
There's the reserved bit (aka the evil bit[1]). Are you saying gear out there drops packets with reserved bit set to 1? Wouldn't surprise me, just curious.
Seems like IPv4+ would have been a good time to use that bit. Any IPv4+ packets could have more flags in the + portion of the header, if needed.
[1]: https://en.wikipedia.org/wiki/Evil_bit