hi, On 9/6/19 11:59 AM, Samuel Thibault wrote: [...] >> 16:49:39.430959 IP 10.0.2.2.33294 > 10.0.2.15.19003: UDP, bad length 9000 > >> 1472 > > Just to be sure: did you configure your guest mru to 9000 ? Does the > emulated network hardware card support jumbo frames?
hm! all interfaces (host and guest) are configured to a mtu of 9000 (except for lo which is always 64k). there's no serial/ppp involved, so i can not set a mru (for non-p2p links the 'mru' kindof should be the mtu of the respective other interface of traffic?). i found no way to configure slirp (in qemu) itself except for the DEFINEs in the if.h. i tried all available nic-emulations, then continued with virtio, which is one that accepts the mtu settings (and sending jumbo frames out does work). the other nics where jumbo frames can be configured do not behave differently. i'm not aware of any (canonical) parameters to set a max size for received packets - i guess when implementing an interface one could decide to truncate according to the mtu (but i guess i would not and i would also argue against it, i guess when i need a mru size for fixed receive-buffers (which i'd try to avoid) i'd assume the mtu). afaik even with ppp mru is just used to signal a max mtu to set to the peer. -- Mit freundlichen Grüßen / Kind regards, Chris Heinze *Network-/System-/DevOps-Engineer* *PreciBake GmbH* Gollierstr. 70 80339 München Deutschland / Germany *P:* +49-(0)-89-2154895-30 <+49.89.2154895.30> *F:* +49-(0)-89-2154895-99 *E:* c.hei...@precibake.com *W:* www.precibake.com <http://www.precibake.com/> Handelsregister / Commercial Register: Amtsgericht München, HRB 206356 Steuer-Nr. / Tax-ID143/172/11644 Umsatzsteuer-ID / VAT registration number: DE290040302 Geschäftsführer / Managing Director: Dr. Ingo Stork-Wersborg Der Inhalt dieser E-Mail ist ausschliesslich fuer den/die bezeichneten Empfaenger bestimmt. Wenn Sie nicht der vorgesehene Adressat dieser E-Mail oder dessen Vertreter sein sollten, so beachten Sie bitte, dass jede Form der Kenntnisnahme, Veroeffentlichung, Vervielfaeltigung oder Weitergabe des Inhalts dieser E-Mail unzulaessig ist. Wir bitten Sie, sich in diesem Fall mit dem Absender der E-Mail in Verbindung zu setzen. Wir moechten Sie ausserdem darauf hinweisen, dass die Kommunikation per E-Mail ueber das Internet unsicher ist, da fuer unberechtigte Dritte grundsaetzlich die Moeglichkeit der Kenntnisnahme und Manipulation besteht. The information contained in this email is intended solely for the recipient(s). Access to this email by anyone else is unauthorized. If you are not the intended recipient, any form of disclosure, reproduction, distribution or any action taken or refrained from in reliance on it, is prohibited. Please notify the sender of this email immediately. We also like to inform you that communication via email over the internet is insecure because third parties may have the possibility to access and manipulate emails.
