On 11 October 2014 13:16:34 CEST, Mathias Kresin <[email protected]> wrote: >Hello, > >querying dnsmasq from a system which uses uClibc can result in a >partly not working name resolution. > >I'm using dnsmasq 2.71 and uClibc 0.9.33.2 on openWRT 14.07 >(mips/x86). The openwrt version of uClibc includes already a lot of >fixes from HEAD. I've checked the commits between $version and HEAD of >both programs and couldn't spot any related change. > >To hit this incompatibility the requested hostname must not a dnsmasq >dhcp client and not mentioned in any hosts file. > >When querying for a _non_ FQDN the uClibc resolver sends first a query >for the hostname only. If the server response code is NXDOMAIN (3) or >SERVERFAIL (2) it resends the query as FQDN using the search value >from /etc/resolv.conf[1]. > >Unfortunately dnsmasqs response code to the query for the hostname is >NOERROR (0). As this isn't s.th. that uClibc does expect in case of a >none existing hostname, the query for the FQDN is never send. > >For reference I checked what other DNS resolvers are doing when >querying for non existent hosts with a search value in resolv.conf >using 'nslookup host': > >linux + uclibc: > 1. query for host > >linux + glibc: > 1. query for host.domain.tld > 2. query for host > >windows7: > 1. query: host.domain.tld > >macos 10.9: > 1. query for host.domain.tld > 2. query for host > >And even what other DNS Servers[2] are returning on 'nslookup host': > >microsoft dns: SERVERFAIL (2) >google public dns: NXDOMAIN (3) >bind 9.10.0-P2 : NOERROR (0) >powerdns: NOERROR (0) > >Due lack of a deeper knowledge of the DNS RFCs I can't say who behaves >wrong here. According to [3],[4] and [5] I'm not the only one who >found the oddity.
http://lists.uclibc.org/pipermail/uclibc/2014-March/048288.html Was the alternative that I did not apply back then in favour of a more conservative fix (IIRC). Can you check if that alternative would work for dnsmasq, please? TIA, > >Regards >Mathias Kresin > >[1] >http://git.uclibc.org/uClibc/tree/libc/inet/resolv.c?id=a9bdc5d28e692c04f51bcea1bb8e87f9c72ad09f#n1463 >[2] http://www.ungefiltert-surfen.de/nameserver/de.html >[3] https://dev.openwrt.org/ticket/13685 >[4] http://freetz.org/ticket/1560 >[5] https://bugs.alpinelinux.org/issues/469 >_______________________________________________ >uClibc mailing list >[email protected] >http://lists.busybox.net/mailman/listinfo/uclibc _______________________________________________ uClibc mailing list [email protected] http://lists.busybox.net/mailman/listinfo/uclibc
