NETGEAR is aware of a growing number of phone and online scams. To learn how to stay safe click here.

Forum Discussion

rossburton's avatar
rossburton
Aspirant
May 29, 2021

Link-local used for IPv6 DNS server

Basically, https://community.netgear.com/t5/Orbi/Bug-RBR20-incorrectly-uses-link-local-router-IPv6-address-as/td-p/1887490   I turned on IPv6 and now my Orbi is telling DHCP clients that the DNS se...
rossburton's avatar
rossburton
Aspirant
May 30, 2021

Aha. So the trick is that you need to specially handle v6 link-local addresses.  The address may be fe80::2a80:88ff:feeb:3cf8 but when it is used it needs to be qualified with the interface name:

 

$ dig @fe80::2a80:88ff:feeb:3cf8%en0 www.aa.net.uk
;; ANSWER SECTION:
www.aa.net.uk.		1287	IN	A	90.155.62.14
www.aa.net.uk.		1287	IN	A	90.155.62.13

And this qualification doesn't make it into /etc/resolv.conf so that's fun to deal with!

CrimpOn's avatar
CrimpOn
Guru - Experienced User
May 30, 2021

I am still thrashing about.  Turns out dig for Windows is a lot easier for me to work with than (anything) on Linux.  (That business with DNS going through the loopback address and all.)

 

Here's what a dig query on  ibm.com looks like from my Orbi liink-local address:

c:\Bind>dig @fe80::a204:60ff:fe1c:239%19 ibm.com ANY

; <<>> DiG 9.16.16 <<>> @fe80::a204:60ff:fe1c:239%19 ibm.com ANY
; (1 server found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 39065
;; flags: qr rd ra; QUERY: 1, ANSWER: 31, AUTHORITY: 0, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 512
;; QUESTION SECTION:
;ibm.com.                       IN      ANY

;; ANSWER SECTION:
ibm.com.                3599    IN      MX      5 mx0b-001b2d01.pphosted.com.
ibm.com.                3599    IN      MX      5 mx0a-001b2d01.pphosted.com.
ibm.com.                19      IN      A       96.17.216.124
ibm.com.                21599   IN      SOA     asia3.akam.net. dnsadm.us.ibm.com. 1564134900 43200 7200 604800 3600
ibm.com.                19      IN      AAAA    2600:1406:3400:6a1::3831
ibm.com.                19      IN      AAAA    2600:1406:3400:69d::3831
ibm.com.                599     IN      TXT     "amazonses:79ShwQazteb+WkCt8e297sAC2mwZVRditsrzaoxiHjU="
ibm.com.                599     IN      TXT     "00D3h000004YkeYEAS"
ibm.com.                599     IN      TXT     "00d50000000c9mweay"
ibm.com.                599     IN      TXT     "yandex-verification: 5f458b477256c50c"
ibm.com.                599     IN      TXT     "00d00000000hedieay"
ibm.com.                599     IN      TXT     "40a21f5affe343c6b37e0a5af80dcd93"
ibm.com.                599     IN      TXT     "Dynatrace-site-verification=76b6b299-fe43-4f31-889b-a8a467193478__8q74sg9dg5udjppn95utrb8bct"
ibm.com.                599     IN      TXT     "v=spf1 ip4:148.163.158.5 ip4:148.163.156.1 ip4:67.231.145.127 ip4:67.231.153.87 ip4:168.245.101.145 mx a:zgateway.zuora.com include:_spf.google.com ~all"
ibm.com.                599     IN      TXT     "atlassian-domain-verification=WAjTH82C5Zx475WLKAA2nrdlsoA/kN0ej9igrLrED4h15KMHPOm+A5H3GndKAxDC"
ibm.com.                599     IN      TXT     "google-site-verification=Jck8mLbYYfCnrmi_nRy4MG2fbUN3UGhC29KdspGLd9Y"
ibm.com.                599     IN      TXT     "adobe-idp-site-verification=5f8adca7-512f-44e1-a5b2-b62c5e3763f2"
ibm.com.                599     IN      TXT     "apple-domain-verification=M3o953J0rN1B0P2a"
ibm.com.                599     IN      TXT     "00df40000004784eaa"
ibm.com.                599     IN      TXT     "google-site-verification=tzdngH5fWH-k8uQoDVovOFJQZTwaGtDOP6S2cQlOvCs"
ibm.com.                599     IN      TXT     "_github-challenge-ibm.ibm.com=2613e984bc"
ibm.com.                599     IN      TXT     "facebook-domain-verification=kyuxs3tdqtyh9rbqa3szkq3k9i2bbs"
ibm.com.                599     IN      TXT     "MS=ms61389031"
ibm.com.                21599   IN      NS      usw2.akam.net.
ibm.com.                21599   IN      NS      asia3.akam.net.
ibm.com.                21599   IN      NS      eur2.akam.net.
ibm.com.                21599   IN      NS      usc3.akam.net.
ibm.com.                21599   IN      NS      ns1-206.akam.net.
ibm.com.                21599   IN      NS      eur5.akam.net.
ibm.com.                21599   IN      NS      ns1-99.akam.net.
ibm.com.                21599   IN      NS      usc2.akam.net.

;; Query time: 134 msec
;; SERVER: fe80::a204:60ff:fe1c:239%19#53(fe80::a204:60ff:fe1c:239%19)
;; WHEN: Sun May 30 15:21:59 Pacific Daylight Time 2021
;; MSG SIZE  rcvd: 1497

 

I am still of the opinion that Orbi giving out its IPv4 and IPv6 link local addresses as DNS servers "works".

I am also of the opinion that IPv6 is incredibly complicated and confusing and that a tremendous portion of the internet is not IPv6 friendly.

 

 

  • CrimpOn's avatar
    CrimpOn
    Guru - Experienced User
    May 30, 2021

    An example of my confusion is the way web browsers totally manipulate the process.

    ford.com and honda.com do not have IPv6 addresses. (www.ford.com has IPv6 but www.honda.com does not).

     

    Open a web browser to http://ford.com (not https and not www.ford.com)  What does the browser produce?  https://www.ford.com

     

    And.... now that I find IPv6 addresses for URL's like www.ford.com, I have yet to get a browser to open the web site using IPv6.

     

    For me, networking continues to be a humbling experience.