MTU question

[Modulok]

On 6/30/07, chloe K <chloekcy2000 at yahoo.ca> wrote:
> Hi all
>
>   ls our network provider insists to set the mtu to 1600? but I can only set
> the freebsd as 1500.
>
>   ls there any network issue?
>
>   thank you

A value of 1600 is not standard compliant. A value of 1500 is the
largest MTU for standard ethernet, as stated in RFC 894 - "A Standard
for the Transmission of IP Datagrams over Ethernet Networks", and RFC
1191 - "Path MTU discovery." Perhaps your provider is confused?

RFC 894:
"...the maximum length of an IP datagram sent over an Ethernet is 1500 octets."


As far as overriding this to a higher value, you may be restricted in
doing so by your hardware, as stated in the ifconfig(8) manpage,
"...Not all interfaces support setting the MTU, and some interfaces
have range restrictions."

-Modulok-