On Wed, 24 Jul 2002, Brian E Carpenter wrote: > Franck, > > ISOC knows about this, but you actually need to contact ISOC's ISP. > > But frankly it's a quixotic mission; SMTP mailers that break when they > find a non-ECN-tolerant SMTP peer are likely to encounter trouble for > some years to come. > > The issue here is that there is a MAY in RFC 3168 that IMHO should > be a SHOULD. That's the first MAY in section 6.1.1.1. If your ECN > code implemented that MAY, you would not have seen a problem. That "hack" was never added to the Linux implementation (dont think you will *ever* see it as part of the Linux TCP code). I am glad we did that: almost all the net sites that had anything to do with fixing their broken boxes to date have had admins who got emails from someone using Linux who told them their site was broken. I dont know what Franck uses but i am willing to bet it is Linux. On the issue of "I should be allowed to block whatever bits i want", i would say if you block ECN you will hear from some rabid Linux user ;-> On a serious note, you can block whatever you want but you should be able to do so on a policy basis: Most of the broken boxen dont provide the admin the option to allow ECN bits (instead hard-coded to drop). And if you had the option and choose and still decide to drop, its almost as helpful as blocking all ICMP packets. cheers, jamal