Jumbo frames generally depends on the drivers for the network card - if the adapter properties has some kind of advanced tab or a separate utility (e.g. the Intel Pro stuff).
With a modern operating system there is a default MTU for the interface (usually 1500, but it can take into account if DHCP gives out a different value).
However MTUs to other destinations are reduced on the fly (by PMTUD) as long as the intervening routes allow ICMP (pings and such).
What this means is if all devices on the LAN can cope with jumbo frames you can try it and a modern OS should end up using the larger MTU on the LAN but a smaller value when talking to the internet (*).
You'll want the router to officially support jumbo frames on the LAN interface as it should by design fragment them for a smaller MTU on the WAN interface, even if a device mistakenly tries to send oversize packets towards the internet.
There are at least 3 factors that might hamper automatic MTU detection / NIC performance:
- If the MTU has been manually tweaked in the past (if there was only a single compromise MTU) the automatic behaviour might have been turned off.
- If a destination site's network admins have block pings (misguided ideas about security) it might take longer to find a working MTU for that path.
- If you have ever used the Windows "detect and repair" network troubleshooter that turns off certain optimisations (favours conservative over speed).
prompt $P - Invalid drive specification - Abort, Retry, Fail? $G
prlzx on n e w n e t Max ADSL