How to clear Don't Fragment (DF) bit

I'll be blunt. You need to read the IP and ethernet standards before making statements about MTU's. Also don't call the MSS a layer-3 MTU. It's not. It's the MSS. Am i being pedantic? Yes. Most assuredly. Not to be an ***. But simply because THAT IS THE STANDARDS. It's why things appear to magically work so well across the whole internet. Because the standards are well written, easy to understand and precise. Yes, violating some of them DOES appear to work. Mostly. Until you discover the edge situations and learn the hard way that violating the standards is a little like dropping litter in Singapore... Just substitute $500 fine for damn thing isn't working... The lack of IMCP unreachable coming back (WHich is the whole cause of this thread) is a Case in point. Sure, not passing them APPEARS to work. But this in itself is one of the edge situations where it breaks. SOMEWHERE in the path between the two endpoints has a lower MTU. It works for SOME people because they're doing stuff correctly. SOMEONE has done something WRONG, which VIOLATES the STANDARDS in the first place. Putting ANOTHER VIOLATION in place to fix them is NOT the right way to do it.

 

 

Of course I can't stop you from violating the standards and you should feel free to do so. After all, it's what keeps me useful to people with deep pockets

 

 

regards

 

hamish