On Wed, 2016-05-11 at 09:23 +0200, Nikos Mavrogiannopoulos wrote: > On Tue, May 10, 2016 at 7:53 PM, Yick Xie <yick.xie at gmail.com> wrote: > > Hello, > > As the title indicated, ocserv just dynamically and frequently adjust > > the MTU value of virtual adapters according to peer-endings, which > > sometimes even was set to 576. But actually the network is still > > stable, only with certain kind of packet loss, yet totally acceptable. > > That's a nice observation. I've reviewed the code, and as it is now, > the MTU is being lowered when the kernel thinks that the MTU is too > big (typically when some router sends an ICMP notification for that). > However there is only logic to account lowering the MTU, but not > raising it when the user's connection is no longer bounded. That is > most likely you see clients (probably on mobile networks) drop to 576 > and never increase their MTU. Note also that when it goes below 1280 you lose IPv6 connectivity. If you really have got an MTU that low on a tunnel with IPv6 configured, then perhaps we should either give up and *allow* fragmentation (over a Legacy IP network), or fall back to sending (the larger frames?) over the TCP connection? -- dwmw2 -------------- next part -------------- A non-text attachment was scrubbed... Name: smime.p7s Type: application/x-pkcs7-signature Size: 5760 bytes Desc: not available URL: <http://lists.infradead.org/pipermail/openconnect-devel/attachments/20160511/12d0fac1/attachment.bin>
