[Dnsmasq-discuss] Can dnsmasq using tcp to query the upstream dns servers?

Discussion:

Hongyi Zhao

2015-10-06 01:11:42 UTC

Hi Simon,

I want to do the following thing with dnsmasq:

1- Query some upstream dns servers with udp for some domains.
2- Query some upstream dns servers with tcp for some domains.

Can this be done?

Regards

--
Hongyi Zhao <***@gmail.com>
Xinjiang Technical Institute of Physics and Chemistry
Chinese Academy of Sciences
GnuPG DSA: 0xD108493

w***@gmail.com

2015-10-06 02:22:11 UTC

Permalink

Post by Hongyi Zhao
Hi Simon,
1- Query some upstream dns servers with udp for some domains.
2- Query some upstream dns servers with tcp for some domains.
Can this be done?

DNS queries always start with udp and then switch to tcp if the response is
larger than the allowed size...

why would one need or want to do as you ask?

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Simon Kelley

2015-10-06 20:30:55 UTC

Permalink

Post by Hongyi Zhao
Hi Simon,
1- Query some upstream dns servers with udp for some domains.
2- Query some upstream dns servers with tcp for some domains.
Can this be done?
Regards

No. The protocol used to contact the upstream server must be the same as
the one used to send the query to dnsmasq. This might change in the
future to allow queries which arive over UDP to be forwarded over TCP,
but at the moment it's a rule without exception.

Cheers,

Simon.