3.4 KiB
| layout | page_title | sidebar_current |
|---|---|---|
| docs | Forwarding | docs-guides-forwarding |
Forwarding DNS queries from Bind To Consul
In order to not have to run Consul as root and bind to port 53 it's best if it's paired with Bind.
In this example, Bind and Consul are running on the same machine
DNSSEC
First, you have to disable DNSSEC so that Consul and Bind can communicate
options {
listen-on port 53 { 127.0.0.1; };
listen-on-v6 port 53 { ::1; };
directory "/var/named";
dump-file "/var/named/data/cache_dump.db";
statistics-file "/var/named/data/named_stats.txt";
memstatistics-file "/var/named/data/named_mem_stats.txt";
allow-query { localhost; };
recursion yes;
dnssec-enable no;
dnssec-validation no;
/* Path to ISC DLV key */
bindkeys-file "/etc/named.iscdlv.key";
managed-keys-directory "/var/named/dynamic";
};
include "/etc/named/consul.conf";
Zone File
Then we set up a zone for our Consul managed records in consul.conf:
zone "consul" IN {
type forward;
forward only;
forwarders { 127.0.0.1 port 8600; };
};
Complete the Setup
Once those files are changed, restarted named (on RHEL this is just 'system named restart') and you should be done.
Testing
First, perform a DNS query against Consul directly to be sure that the record exists:
[root@localhost ~]# dig @localhost -p 8600 master.redis.service.dc-1.consul. A
; <<>> DiG 9.8.2rc1-RedHat-9.8.2-0.23.rc1.32.amzn1 <<>> @localhost master.redis.service.dc-1.consul. A
; (1 server found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 11536
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 0
;; QUESTION SECTION:
;master.redis.service.dc-1.consul. IN A
;; ANSWER SECTION:
master.redis.service.dc-1.consul. 0 IN A 172.31.3.234
;; Query time: 4 msec
;; SERVER: 127.0.0.1#53(127.0.0.1)
;; WHEN: Wed Apr 9 17:36:12 2014
;; MSG SIZE rcvd: 76
Then run the same query against your Bind instance and make sure you get a result:
[root@localhost ~]# dig @localhost -p 53 master.redis.service.dc-1.consul. A
; <<>> DiG 9.8.2rc1-RedHat-9.8.2-0.23.rc1.32.amzn1 <<>> @localhost master.redis.service.dc-1.consul. A
; (1 server found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 11536
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 0
;; QUESTION SECTION:
;master.redis.service.dc-1.consul. IN A
;; ANSWER SECTION:
master.redis.service.dc-1.consul. 0 IN A 172.31.3.234
;; Query time: 4 msec
;; SERVER: 127.0.0.1#53(127.0.0.1)
;; WHEN: Wed Apr 9 17:36:12 2014
;; MSG SIZE rcvd: 76
Troubleshooting
If you don't get an answer from Bind but you do get an answer from Consul then your best bet is to turn on the query log to see what's going on
[root@localhost ~]# rndc querylog
[root@localhost ~]# tail -f /var/log/messages
In there if you see errors like this:
error (no valid RRSIG) resolving
error (no valid DS) resolving
Then DNSSEC is not disabled properly. If you see errors about network connections then verify that there are no firewall or routing problems between the servers running Bind and Consul