<br><br><div class="gmail_quote">On Mon, Jan 10, 2011 at 1:40 PM, Nicholas Weaver <span dir="ltr"><<a href="mailto:nweaver@gmail.com">nweaver@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">
<div class="im">><br>
> Oh nevermind, it affect the TCP option negotiation, so it causes the client<br>
> to send smaller packets. So it is a general solution for TCP (and only<br>
> TCP). For UDP, the mtu still needs to be reduced at the client.<br>
<br>
</div>All but linux however do the right thing on UDP and don't send it with<br>
DF sent, which means it should be refragmented if it goes through a<br>
bottleneck. (Of course, ~10% of the systems on the Internet can't<br>
process UDP fragments, but thats orthoginal (usually) to the PMTU<br>
problems)<br>
</blockquote></div><br><div>How so? If the sender MTU is set to the PMTU, then fragmentation won't be needed, and systems that drop fragments won't become an issue.</div>