ath using hostap sets MTU to 2290

Sam Leffler sam at
Tue Jul 29 20:41:05 UTC 2008

John T. Yocum wrote:
> Hello,
> I have a system running pfSense, which is built on top of FreeBSD 
> 7.0-RELEASE-p3. In the system I have an Atheros wireless card, which 
> when I enable hostap, changes it's MTU to 2290. If an explanation is 
> listed on a man page, I apologize, I did try searching.
> Any ideas why this might happen? It doesn't appear to be a pfSense 
> issue, as it appears their code actually tries to set the MTU to 1500.
> Only reason I ask here, is I noticed in my searching on Google, I 
> noticed others that aren't running pfSense have their MTU set to 2290.
MTU on an 802.11 network is 2290.  If you don't want the default then 
change it.  If you cannot then please provide the exact steps you take 
that do not work.


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