edns-buffer-size

Unbound
1

unbound.conf
# EDNS reassembly buffer to advertise to UDP peers (the actual buffer
# is set with msg-buffer-size). 1480 can solve fragmentation (timeouts)
edns-buffer-size:

Why does this comment recommend
1480 = 1500 - 20 ? (UDP datagram size over IPv4)

Why is this value not to become
1472 = 1500 - 20 - 8 ? (UDP payload size over IPv4)

Or, Is this a value of another meaning?

(I verified that the edns-buffer-size is used for udp payload size of EDNS0.)

2

Hi T.Suzuki,

Yes, 1472 is a more precise value to recommend. Changed the example
config and also the man page.

Best regards, Wouter

3

And for IPv6 header?

4

And for IPv6 header?

On general Ethernet,

1452 = 1500-40-8

However, some people who do not believe PMTUD are using 1280 as minimum MTU.

So,

1232 = 1280-40-8

will be more safety.

But I do not want use EDNS0. It is very wastefull for other than DNSSEC user.

I want to enable DO bit. Can I do with Unbound? (However I know it's "MUST" by RFC.)