On 21 Aug 2014, at 18:10, Joe Touch <[email protected]> wrote: > > > On 8/21/2014 8:47 AM, Brian Trammell wrote: >> hi Joe, all, >> >> okay, I'm convinced for passive FTP (and s/FTP/active-mode FTP/g in >> myprevious message). >> >> Now the problem would remain -- how, in an interfaceless >> environment, can the tcpinc machinery tell passive from active FTP in >> advance? > > Why would it want/need to, any more than IPsec over UDP would?
... ah, right, because the subsequent passive-mode connection would Just Work. (Please forgive my rustiness with FTP; I honestly don't know whether I've used it directly this century.) > However, a SYN issued from port 20 would tell you it's active. > >> One possible approach here would be to detect a failed >> active FTP transaction, then rely on the application to try again and >> remember to disable itself for the second attempt (kind of like >> Valery's option 4, but with fallback). > > FTP users already know to try passive mode FTP, AFAICT. Yep... if this is the case, then there's no problem here. Cheers, Brian >> Of course this leads to the type of implementation complexity I was >> hoping to avoid through deprecation. I still think any pressure we can >> exert to speed active-mode FTP's retirement is effort better spent than >> effort building fiddly bits into tcpinc (Valery's option 6) for this >> corner case. > > There's no need tor retire anything. You can just recommend that the default > is to use passive mode if you want, though. > > Joe > > > _______________________________________________ > Tcpinc mailing list > [email protected] > https://www.ietf.org/mailman/listinfo/tcpinc
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