Hi Richard Wendland of netcraft said the following about recognizing the Hurd/pfinet. Most of it is above my head, so I send it to the list in case someone who understands more of it wants to give it a shot.
I think pfinet recognized as "unknown" would be a step up from being listed as "Linux". :) Oystein ,---- | First I should say I can't guarantee we'd recognise Hurd as "Hurd", | as usual policy is only to recognise OSs with > 50 sites, just to avoid | effort regularly validating etc. At the moment Hurd doesn't get there - | though I expect it will. But I would stop it being recognised as Linux | if I could - "unknown" initially perhaps. | | I can't disclose the exact method, but in part it looks at the obvious | things like window size and TCP options. | | For example if you changed the default window size to something unusual | for Linux, from 32k it currently is to say 24k or 36k, that would probably | get you as "unknown" without any action on my part. You could test this | on your box with an option or /proc, or maybe a simple source tweak. | | We'd need a more significant change to positively recognise Hurd. Say as | well as a different window size changing the order of TCP options on | SYN-ACK, say changing the order MSS & timestamp & window scale is added | in the source code; swapping window scale & timestamp might be easy. | | | BTW there is a small inefficiency in the Linux TCP version you picked up. | When using TCP timestamp option, as you do by default, the data load of | full TCP segments is 12 bytes less than MSS (to make space for timestamp), | eg 1448 bytes for the usual 1460 MSS. TCPs often round offered window | size to a multiple of data load to reduce risk of partial segments | being sent. But in the Linux TCP version Hurd uses it rounds to a | multiple of MSS (ie 32120 = 22*1460), but it would be better to round | to multiple of 1448 (ie 22*(1460-12) = 31856, or 23*(1460-12) = 33304). | | That would also be a feature I could recognise. | | Regards, | | Richard | -- | Richard Wendland [EMAIL PROTECTED] `----