On Tue, 06 Mar 2007 14:07:09 -0800 Howard Chu <[EMAIL PROTECTED]> wrote:
> David Miller wrote: > > From: Rick Jones <[EMAIL PROTECTED]> > > Date: Tue, 06 Mar 2007 13:25:35 -0800 > > > >>> On the other hand, being able to configure a small MSL for the loopback > >>> device is perfectly safe. Being able to configure a small MSL for other > >>> interfaces may be safe, depending on the rest of the network layout. > >> A peanut gallery question - I seem to recall prior discussions about how > >> one cannot assume that a packet destined for a given IP address will > >> remain detined for that given IP address as it could go through a module > >> that will rewrite headers etc. > > > > That's right, both netfilter and the packet scheduler actions > > can do that, that's why this whole idea about changing the MSL > > on loopback by default is wrong and pointless. > > If the headers get rewritten and the packet gets directed elsewhere, > then we're no longer talking about a loopback connection, so that's > outside the discussion. > > If the packet gets munged by multiple filters but still eventually gets > to the specified destination, OK. But regardless, if both endpoints of > the connection are on the loopback device, then there is nothing wrong > with the idea. Those filters can only do so much, they still have to > preserve the reliable in-order delivery semantics of TCP, otherwise the > system is broken. > > It may not have much use, sure, I admitted that much from the outset. > > So I'll leave it at this, thanks for the feedback. TCP can not assume anything about the path that a packet may take. We have declared a moratorium on loopback benchmark foolishness. Go optimize the idle loop instead ;-) -- Stephen Hemminger <[EMAIL PROTECTED]> - To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
