I am trying to prevent a webserver to do IPv6 lookups (AAAA) to the DNS-server. The webserver has no IPv6 addresses set-up on the interfaces. Disabling IPv6 in sysctl.conf had no impact either, the webserver keeps sending both A and AAAA requests for every hostname to the DNS server (I performed a tcpdump).
Can anyone help me with stopping the webserver to send out IPv6 hostname lookups?
This is on my internal network. TCPDump:
webserver.internal.43831 > internaldns.internal.domain: [bad udp cksum 629d!] 63585+ A? someserver.internal. (43)` webserver.internal.43831 > internaldns.internal.domain: [bad udp cksum 32dd!] 40337+ AAAA? someserver.internal. (43)
internaldns returns the IP for the A-record and NXDOMAIN for the AAAA, as there isn't set one.