Re: [DNSOP] I-D Action: draft-ietf-dnsop-avoid-fragmentation-02.txt

Hello. We submitted draft-ietf-dnsop-avoid-fragmentation-02.

Authors simplified recommendations.

Main recommendations are setting IP_DONTFRAG / IPV6_DONTFRAG options
and compose DNS packets fit in path MTU.
Then, DNS UDP responses are fragmentation free.

If people want to use large packet size (with path MTU discovery),
they need to calculate EDNS0 size from path MTU size.

However, many people wants static recommendaton value for EDNS0 size.

I'm wondering if it's better to write a recommended MTU value or a
recommended EDNS0 size.

--
Kazunori Fujiwara, JPRS <fujiwara@jprs.co.jp>

> From: internet-drafts@ietf.org
> A New Internet-Draft is available from the on-line Internet-Drafts directories.
> This draft is a work item of the Domain Name System Operations WG of the IETF.
> 
>         Title           : Fragmentation Avoidance in DNS
>         Authors         : Kazunori Fujiwara
>                           Paul Vixie
> 	Filename        : draft-ietf-dnsop-avoid-fragmentation-02.txt
> 	Pages           : 10
> 	Date            : 2020-09-15
> 
> Abstract:
>    EDNS0 enables a DNS server to send large responses using UDP and is
>    widely deployed.  Path MTU discovery remains widely undeployed due to
>    security issues, and IP fragmentation has exposed weaknesses in
>    application protocols.  Currently, DNS is known to be the largest
>    user of IP fragmentation.  It is possible to avoid IP fragmentation
>    in DNS by limiting response size where possible, and signaling the
>    need to upgrade from UDP to TCP transport where necessary.  This
>    document proposes to avoid IP fragmentation in DNS.
> 
> 
> The IETF datatracker status page for this draft is:
> https://datatracker.ietf.org/doc/draft-ietf-dnsop-avoid-fragmentation/
> 
> There are also htmlized versions available at:
> https://tools.ietf.org/html/draft-ietf-dnsop-avoid-fragmentation-02
> https://datatracker.ietf.org/doc/html/draft-ietf-dnsop-avoid-fragmentation-02
> 
> A diff from the previous version is available at:
> https://www.ietf.org/rfcdiff?url2=draft-ietf-dnsop-avoid-fragmentation-02
> 
> 
> Please note that it may take a couple of minutes from the time of submission
> until the htmlized version and diff are available at tools.ietf.org.
> 
> Internet-Drafts are also available by anonymous FTP at:
> ftp://ftp.ietf.org/internet-drafts/
> 
> 
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