[dns-wg] How to determine the last message in sequence in DNS TCP responce

On 27/02/2019 17:21, Владимир Мартьянов wrote:

Hi Vladimir,

> I make DNS zone transfer request (aka AXFR) via TCP to the server. The
> answer is too big (>100Kb), so it could not be sent in one TCP
> message. So the server send me a sequence of messages.
> 
> How can I determine which message is the last? I can't found anything
> about it's count in the first message. I can't found any special flag
> in the last one. I can't found anything about it in RFC1035.
> 
> Could you please explain how to find "end of answer"?

A zone transfer starts with the SOA record of the zone, and ends with
the same SOA record. That's how you know that the transfer is complete.

To learn more about zone transfers, see RFC 5936, section 2.2:

https://tools.ietf.org/html/rfc5936

Regards,
Anand Buddhdev
RIPE NCC