Find the answer to your Linux question:
Results 1 to 2 of 2
Enjoy an ad free experience by logging in. Not a member yet? Register.
  1. #1

    DNS queries with type=28 (AAAA, for IPV6)


    For some time, my browser was refreshing pages very slowly, and after suggestions
    from other members, I added entries into /etc/modprobe.conf.
    After adding those entries in /etc/modprobe.conf,
    the browsers refresh the pages very fast. The DNS queries are with type =1
    (A, IPV4 address) and the response from nameserver is seen immediately.

    However, there are some applications that still use IPV6 address in their
    queries. I have configured evolution (as a POP3 mail client) to get emails
    from gmail and here is the capture (from ethereal!)

    15 31.33984 192.168.1.102 -> 192.168.1.1 DNS C pop.gmail.com. Internet AAAA ?
    16 0.07952 192.168.1.1 -> 192.168.1.102 DNS R pop.gmail.com. Internet Addr 64.233.171.111
    17 4.92045 192.168.1.102 -> 192.168.1.1 DNS C pop.gmail.com. Internet AAAA ?
    18 0.09158 192.168.1.1 -> 192.168.1.102 DNS R pop.gmail.com. Internet Addr 64.233.171.111
    19 4.90785 192.168.1.102 -> 192.168.1.1 DNS C pop.gmail.com.hsd1.ca.comcast.net. Internet AAAA ?
    20 5.05421 192.168.1.102 -> 192.168.1.1 DNS C pop.gmail.com.hsd1.ca.comcast.net. Internet AAAA ?
    21 5.01862 192.168.1.102 -> 192.168.1.1 DNS C pop.gmail.com. Internet Addr ?
    22 0.09515 192.168.1.1 -> 192.168.1.102 DNS R pop.gmail.com. Internet Addr 64.233.171.111

    If we look at the details of one packet (15 from above), we can see the query type is 28 (for
    IPV6 address)

    DNS: ----- DNS Header -----
    DNS:
    DNS: Query ID = 31116
    DNS: Opcode: Query
    DNS: RD (Recursion Desired)
    DNS: 1 question(s)
    DNS: Domain Name: pop.gmail.com.
    DNS: Class: 1 (Internet)
    DNS: Type: 28 (IPv6 Address) <------------ IPV6
    DNS:

    Mozilla for example sends the request correctly, as seen from this

    DNS: ----- DNS Header -----
    DNS:
    DNS: Query ID = 38534
    DNS: Opcode: Query
    DNS: RD (Recursion Desired)
    DNS: 1 question(s)
    DNS: Domain Name: ads.rediff.com.
    DNS: Class: 1 (Internet)
    DNS: Type: 1 (Address)
    DNS:

    In spite of disabling IPV6 through modprobe.conf, why are some applications
    still sending DNS queries with IPV6 address ? Even if it were to send those,
    my name server seems to be responding right away and still the client
    sends the query after another 5 seconds?

    How do we circumvent this problem?

  2. #2
    On the machine that is sending these AAAA queries, are you using the local BIND to resolve all domains? If so, what is your version of BIND?

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •