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[lwip-users] DNS look-up with domain search
From: |
Craig McQueen |
Subject: |
[lwip-users] DNS look-up with domain search |
Date: |
Sun, 11 Nov 2018 23:26:13 +0000 |
I'm interested in doing DNS look-ups that possibly include a domain search list.
I'm successfully using LWIP_HOOK_DHCP_APPEND_OPTIONS() and
LWIP_HOOK_DHCP_PARSE_OPTION() to get a domain from DHCP via DHCP option 15.
Now I'm interested in possibly using that as a search domain. So if doing a
look-up for "server", and DHCP option 15 specifies domain "example.com", then
DNS could do a search for "server.example.com". But not if the original look-up
name includes a trailing dot. If the original name includes a trailing dot,
e.g. "server.com.", then it wouldn't try "server.com.example.com".
Note that the current functions in dns.c will fail a DNS look-up given a string
that ends with a trailing dot. Technically is this correct or incorrect? See
the following which discusses trailing dots in domain names:
http://www.dns-sd.org/trailingdotsindomainnames.html
--
Craig McQueen
- [lwip-users] DNS look-up with domain search,
Craig McQueen <=