On Fri, 1 Aug 2008, Vasiliy Baranov wrote:

> In BIND, is there an "additional local" limit on the payload size of
> EDNS responses the server can send? Is it configurable? edns-udp-size
> sets the advertised buffer size for responses going TO the server. Is it
> also used as the limit on responses going FROM the server (in addition
> to the limit advertised by the client)?
>
> In other words, if my authoritative nameserver is behind a device that
> drops outgoing fragmented packets, can I configure BIND to not send EDNS
> responses that would require fragmentation?
>
> BIND 9.3.5-P1, if that matters.


From the latest 9.4.x ARM:

The max-udp-size option sets the
maximum EDNS UDP message size named will send. Valid
values are 512 to 4096 bytes (values outside this range will
be silently adjusted). This option is useful when you
know that there is a firewall that is blocking large
replies from named.

It is independent of the advertised receive buffer (edns-udp-size).

Sorry it is not in your version. It was introduced in 9.4.0.