Thanks, Khaled. I appreciate you offering details - especially knowing now that you're no longer a regular. (Which makes me feel horribly guilty asking as a follow-up what 'some situations' are re: PDCC.
Anyway, I agree with leaving /pdcc and /fsend intact. It's nice having that configurability handy. "/fsend off" gives the possibility of perfect DCC RFC compliance, and "/pdcc on" surely gives someone, somewhere a little extra throughput.
With broadband speed lust being the norm now, I've been wondering to myself lately if there's any way left of optimizing average DCC speeds without violating the DCC "RFC". Two things have occurred to me: larger packet sizes, and basing packet sizes on multiples of the sender's MSS (rather than on multiples of 512 as now). So if my client detected that my current MSS was 1460, then it would give me packet size choices of, say, 730 (1/2 MSS), 1460, 2920, 5840, 11680, 23360, 46720, and 93440.
If you think there's any logic to this, toy with it some time and see what happens. Else, disregard.
@Argv0 - In fact, my last visit to this forum was 11 months ago. Khaled was active then (he responded to some of my posts), and I didn't know anything had changed. So if my "top secret" remark seemed arrogant, it wasn't meant to be. I thought he was still as active as ever.
BTW, I thought about using a packet sniffer too, but realized I'd never truly get to the bottom of the mystery because I'd also have to rig the recipient to somehow stop sending ACKs at some point in order to observe the sender's behavior in response.