Tag Archives: bind

My Debian Activities in June 2019

FTP master

As you might have noticed as well, this month has been a month with the highest average temperature of all June so far. So I spent more time in the lake than in NEW. I only accepted 12 packages and rejected 1 upload. The rest of the team probably did the same because the overall number of packages that got accepted was only 22. Let’s see whether July will be the same …

Debian LTS

This was my sixtieth month that I did some work for the Debian LTS initiative, started by Raphael Hertzog at Freexian.

This month my all in all workload has been 17h. During that time I did LTS uploads or prepared security uploads of:

  • [DLA 1830-1] znc security update for one CVE
  • [DLA 1833-1] bzip2 security update for two CVEs
  • [DLA 1841-1] gpac security update for three CVEs

I also prepared bzip2 debdiffs for Buster and Stretch and sent them to the maintainer and security team.
Further I created new packages for testing the patches of bind9 and wpa. I would be more confident to upload those if more people could give it a try. Especially after the python issue, I would really like to have some more people to do smoke tests …

Last but not least I did some days of frontdesk duties.

Debian ELTS

This month was the thirteenth ELTS month.

During my allocated time I uploaded:

  • ELA-132-1 of bzip2 for two CVEs
  • ELA-138-1 of ntfs-3g for one CVE

As like LTS, I am a bit hesitant to upload bind9

I also did some days of frontdesk duties.

Other stuff

As already written above, I did not do much work in front of a computer, so there is nothing to report here.
Ok, maybe I can mention this email here instead of the LTS section above. This is a script to obtain the correct build order of Go packages in case of security patches. As well as mentioned in the other paragraphs I would like more people to have a look at it, but please be kind :-).

bind: rndc addzone and also-notify

Notice to my future self: If you add zones to bind by rndc addzone please remember that those zones will be stored in /var/cache/bind/*.nzf. If you have to change your nameservers, you also need to adapt the also-notify list in all zones. If you forget one zone and there is one unused ip address in that list, all slaves will get the notification, start the transfer but the update won’t happen and the old data remain on the slave.

This sounds really crazy, but think about April 2018, when the challenge for your letsencrypt certificate was added to the master server but never reached the slaves. The log was full of


ERROR: Challenge is invalid! (returned: invalid) (result: {
"type": "dns-01",
"status": "invalid",
"error": {
"type": "urn:acme:error:unauthorized",
"detail": "Incorrect TXT record \"xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx\" found at _acme-challenge.xxxxxxxxx",
"status": 403
},

Let other devices use my own NTP server

I have these fine set-top boxes here, that try to synchronize their time with some external NTP servers.

The names of the NTP servers are coded into the firmware and can not be changed in the network settings menu. They are called ntp1.technibutler.de, ntp2.technibutler.de and ntp3.technibutler.de. Though they are already Stratum 2 servers, I would rather use my own, local DCF77 radio clock. Obviously it makes no sense to contact some server in the wide internet to get information that is already available locally.

Luckily those servers are just used for time synchronization and nobody wants to get web pages from them or wants to send emails to them. So all that needs to be done is to redefine their address resolution in DNS.

In a first step, I configure my own DNS server. The example below are config files for bind9. Any other DNS server should work as well, just pretend that you are authorized to answer queries for the technibutler NTP servers. As long as there is no DNSSEC or secure NTP involved, everything is fine.

First I need to define the different zones. As there might be other services within the technibutler.de zone, that I still want to use, I will define an extra zone for each hostname of the NTP servers.

;
$TTL    86400
@       IN      SOA     ntp1.technibutler.de. redefined-dns.alteholz.de. (
                              1         ; Serial
                         604800         ; Refresh
                          86400         ; Retry
                        2419200         ; Expire
                          86400 )       ; Negative Cache TTL
;
@       IN      NS      localhost.
@       IN      A       10.10.10.1
;
$TTL    86400
@       IN      SOA     ntp2.technibutler.de. redefined-dns.alteholz.de. (
                              1         ; Serial
                         604800         ; Refresh
                          86400         ; Retry
                        2419200         ; Expire
                          86400 )       ; Negative Cache TTL
;
@       IN      NS      localhost.
@       IN      A       10.10.10.1
;
$TTL    86400
@       IN      SOA     ntp3.technibutler.de. redefined-dns.alteholz.de. (
                              1         ; Serial
                         604800         ; Refresh
                          86400         ; Retry
                        2419200         ; Expire
                          86400 )       ; Negative Cache TTL
;
@       IN      NS      localhost.
@       IN      A       10.10.10.1

I store those configs in /etc/bind/redefined/db.ntp1.technibutler.de, /etc/bind/redefined/db.ntp3.technibutler.de and /etc/bind/redefined/db.ntp3.technibutler.de. The only IP address that is needed in these files are the actual IP address of my local NTP server. As I just have only one, all NTP servers from technibutler.de need to point to this address.

Now I have to tell bind that my zones are the master zone. This is done in /etc/bind/redefined/redefined-zones.conf:

zone "ntp1.technibutler.de" {
   type master;
   file "/etc/bind/redefined/db.ntp1.technibutler.de";
};

zone "ntp2.technibutler.de" {
   type master;
   file "/etc/bind/redefined/db.ntp2.technibutler.de";
};

zone "ntp3.technibutler.de" {
   type master;
   file "/etc/bind/redefined/db.ntp3.technibutler.de";
};

And last but not least I have to tell bind9 to load this config during startup. So I add a line:

include "/etc/bind/redefined/redefined-zones.conf";

at the beginning of /etc/bind/named.conf.local

And voila, before that configuration:

$ nslookup ntp1.technibutler.de
Server:         10.10.10.254
Address:        10.10.10.254#53

Non-authoritative answer:
Name:   ntp1.technibutler.de
Address: 62.138.2.9

and after that configuration:

$ nslookup ntp1.technibutler.de
Server:         10.10.10.254
Address:        10.10.10.254#53

Non-authoritative answer:
Name:   ntp1.technibutler.de
Address: 10.10.10.1

After the configuration of your DNS server is done, you just need to point the set-top boxes or any other device in your home network to your own DNS server. You can either deliver this information via “option domain-name-servers” with DHCP, or manually put your DNS server in the network settings of your device.