Can a NAPTR query over TCP contain OPT section in Additional Records

[Mukund Sivaraman]

Hi Harshith

On Thu, Jun 22, 2017 at 05:36:12AM -0700, Harshith Mulky wrote:
> Client                                                                    
> DNS
>             EDNS query, buffer size=4096
>  ------------------------------------------------------->
> 
>                DNS Response, Truncation bit set (TC=1)
> <-------------------------------------------------------
> 
>                           DNS Query over TCP
> ------------------------------------------------------->
> 
>                          DNS Response over TCP
> <------------------------------------------------------
> 
> In the above Call Scenario, I have the Client supporting, edns Buffer
> Size=4096. and on the server, I have enabled this: to limit the server
> sending > 512 bytes in Response
> 
> server 0.0.0.0/0  {
>         edns yes;
>         edns-udp-size 512; //max size query sever can receive is upto 4096
> bytes(default value=4096 )
>         max-udp-size 512; //max size server can transfer is upto 4096
> bytes(default value =4096)
> };

It is not clear what it is you're trying to achieve from the config
block above, but it isn't a good idea to limit to 512 for /0.

> The EDNS query is OK, the response is also OK
> 
> The question is regarding the DNS Query over TCP,
> Can the DNS Query over TCP include the OPT RR section, is this not
> Applicable to only UDP? is there any RFC which supports OPT RR section for
> query over TCP

Yes, the OPT RR carries other information and EDNS options between
client<->nameserver. E.g., without the OPT RR, how will a client tell
the nameserver that DNSSEC is OK (DO=1) ?

>                 Bit 0 (DO bit): 1 (Accepts DNSSEC security RRs)

		Mukund