I've attempted searching just about anywhere I could find to figure out why a seemingly legitimate setup isn't working. I'm trying to archive DDNS with OpenVPN clients utilizing the --learn-address of the OpenVPN server. The DNS server is bind9. I'm not sure about 3 things:
- Are my nameservers correct?
- Why am I getting SERVFAIL?
- When I ping 587-gc2 (or 587-gc2.proxy.example.com) I get
Name or service not known, even as my zone file is currently with a manual entry.
db.vpn zone file in /var/lib/bind/:
$ORIGIN .
$TTL 60 ; 1 minute
proxy.example.com IN SOA ns4.example.com. (
20180711 ; serial
60 ; refresh (1 minute)
120 ; retry (2 minutes)
60 ; expire (1 minute)
60 ; minimum (1 minute)
)
NS ns1.example.com.
NS ns4.example.com.
$ORIGIN proxy.example.com.
$TTL 14400 ; 4 hours
587-gc2 A 172.XX.XX.26
Attempted nsupdate query:
Outgoing update query:
;; ->>HEADER<<- opcode: UPDATE, status: NOERROR, id: 17693
;; flags:; ZONE: 1, PREREQ: 0, UPDATE: 1, ADDITIONAL: 1
;; ZONE SECTION:
;proxy.example.com. IN SOA
;; UPDATE SECTION:
587-gc2.proxy.example.com. 60 IN A 172.XX.XX.26
;; TSIG PSEUDOSECTION:
keyname. 0 ANY TSIG hmac-md5.sig-alg.reg.int. 1531335476 300 16 TSIGSECRET 17693 NOERROR 0
Reply from above nsupdate query:
Reply from update query:
;; ->>HEADER<<- opcode: UPDATE, status: SERVFAIL, id: 17693
;; flags: qr; ZONE: 1, PREREQ: 0, UPDATE: 0, ADDITIONAL: 1
;; ZONE SECTION:
;proxy.example.com. IN SOA
;; TSIG PSEUDOSECTION:
SECRETKEY. 0 ANY TSIG hmac-md5.sig-alg.reg.int. 1531335476 300 16 TSIGSECRET 17693 NOERROR 0
full syslog logs (named log) while reconnecting device
setup_system()
Creating key...
namefromtext
keycreate
reset_system()
user_interaction()
do_next_command()
message repeated 3 times: [ do_next_command()]
evaluate_update()
update_addordelete()
do_next_command()
start_update()
send_update()
Sending update to 127.0.0.1#53
show_message()
update_completed()
tsig verification successful
show_message()
Reply from update query:
;; ->>HEADER<<- opcode: UPDATE, status: SERVFAIL, id: 36239
;; flags: qr; ZONE: 1, PREREQ: 0, UPDATE: 0, ADDITIONAL: 1
;; ZONE SECTION:
;proxy.example.com. IN SOA
;; TSIG PSEUDOSECTION:
SECRETKEY. 0 ANY TSIG hmac-md5.sig-alg.reg.int. 1531416897 300 16 TSIGSECRET 36239 NOERROR 0
done_update()
reset_system()
user_interaction()
cleanup()
detach tsigkey x0x7fb6a35cf0b8
Shutting down task manager
shutdown_program()
Shutting down request manager
Destroy DST lib
Destroying request manager
Freeing the dispatchers
Shutting down dispatch manager
Destroying event
Shutting down socket manager
Shutting down timer manager
Destroying hash context
Destroying name state
Removing log context
Destroying memory context
--learn-address script in /usr/local/sbin/
#!/usr/bin/php
<?php
/*
* This script can be passed to --learn-address of the openvpn server, it will
* update the local bind9 server whenever an ip address is passed
*/
// Bind9 server to update
define("NS_ADDR", "127.0.0.1");
// Domain to prepend common name to
define("DOMAIN", "proxy.example.com");
// nsupdate bin
define("NSUPDATE", "/usr/bin/nsupdate");
// Temp path
define("TMP_PATH", "/tmp/");
// Private key path
define("PRIVATE_KEY", "SECRETKEY:SECRETHASH");
// Debug
define("DEBUG", true);
function failWithError($error) {
syslog(LOG_ERR, $error);
exit(1);
}
function addRecordWithIP($record, $ip) {
$domain = $record.".".DOMAIN;
$filepath = TMP_PATH."/". __FUNCTION__."_" .rand(900, 999);
$fh = fopen($filepath, "w");
fwrite($fh, "server ".NS_ADDR."\n");
fwrite($fh, "debug ".(DEBUG?'yes':'no')."\n");
fwrite($fh, "zone ".DOMAIN."\n");
fwrite($fh, "update add {$domain} 60 A {$ip}\n");
fwrite($fh, "send\n");
fclose($fh);
$output = [];
exec(NSUPDATE." -y ".PRIVATE_KEY." -D -v ".escapeshellarg($filepath).(DEBUG?"":" 2>&1 > /dev/null"), $output);
if (DEBUG) {
syslog(LOG_ERR, print_r($output, true));
}
// clean up
unlink($filepath);
}
function removeRecord($record) {
$domain = $record.".".DOMAIN;
$filepath = TMP_PATH."/". __FUNCTION__."_" .rand(900, 999);
$fh = fopen($filepath, "w");
fwrite($fh, "server ".NS_ADDR."\n");
fwrite($fh, "debug ".(DEBUG?'yes':'no')."\n");
fwrite($fh, "zone ".DOMAIN."\n");
fwrite($fh, "update delete {$domain}\n");
fwrite($fh, "send\n");
fclose($fh);
$output = [];
exec(NSUPDATE." -y ".PRIVATE_KEY." -v ".escapeshellarg($filepath).(DEBUG?"":" 2>&1 > /dev/null"), $output);
if (DEBUG) {
syslog(LOG_ERR, print_r($output, true));
}
// clean up
unlink($filepath);
}
if ($argc < 3) {
failWithError("Incorrect number of params");
}
$slashpos = strpos($argv[2], "/");
if ($slashpos !== false) {
// Remove subnet from ip
$argv[2] = substr($argv[2], $slashpos);
}
if (inet_pton($argv[2]) === false) {
failWithError("{$argv[2]} is not a valid ip address");
}
switch($argv[1]) {
case "update":
case "add":
if (isset($argv[3])) {
removeRecord($argv[3]);
addRecordWithIP($argv[3], $argv[2]);
}
break;
case "remove":
// Since openvpn only provides the ip on this request we cannot remove the
break;
}
// Success
exit(0);
named.conf.local in /etc/bind/:
include "/etc/bind/named.conf.log";
acl vpnnets { 172.XX.XX.XX/16; 192.168.3.0/24; };
acl ourservers { SERVERIP; };
key dhcpupdate {
algorithm hmac-md5;
secret "SECRETHASH";
};
view "vpn" {
match-clients { vpnnets;ourservers; };
recursion yes;
zone "proxy.example.com" {
type master;
file "/var/cache/bind/db.vpn";
allow-update { key SECRETKEY;};
};
include "/etc/bind/named.conf.default-zones-vpn";
allow-query { vpnnets;ourservers;any; };
allow-query-cache { vpnnets;ourservers; };
allow-recursion { vpnnets;ourservers; };
};
view "external" {
match-clients {any;};
recursion yes;
zone "proxy.example.com" {
type master;
file "/var/cache/bind/db.vpn-external";
allow-update { key SECRETKEY;};
};
};
resolv.conf in /etc/:
# This file is managed by man:systemd-resolved(8). Do not edit.
#
# This is a dynamic resolv.conf file for connecting local clients directly to
# all known uplink DNS servers. This file lists all configured search domains.
#
# Third party programs must not access this file directly, but only through the
# symlink at /etc/resolv.conf. To manage man:resolv.conf(5) in a different way,
# replace this symlink by a static file or a different symlink.
#
# See man:systemd-resolved.service(8) for details about the supported modes of
# operation for /etc/resolv.conf.
nameserver 172.XX.XX.1
nameserver 169.254.169.254
search c.GOOGLEPROJECT.internal google.internal
dig output from 587-gc2.proxy.example.com
; <<>> DiG 9.11.3-1ubuntu1.1-Ubuntu <<>> 587-gc2.proxy.example.com
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: SERVFAIL, id: 50282
;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 0, ADDITIONAL: 1
;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 4096
; COOKIE: 3e50511a4a2fe8a1f5ba4f2d5b47943d6559b3ba4abf601e (good)
;; QUESTION SECTION:
;587-gc2.proxy.example.com. IN A
;; Query time: 46 msec
;; SERVER: 172.XX.XX.1#53(172.XX.XX.1)
;; WHEN: Thu Jul 12 12:47:41 CDT 2018
;; MSG SIZE rcvd: 86
named/bind log when trying to dig the fully 587-gc2.proxy.example.com
13-Jul-2018 12:49:49.445 queries: info: client @0x7f69407fa110 172.XX.XX.1#54377 (587-gc2.proxy.example.com): view vpn: query: 587-gc2.proxy.example.com IN A +E(0)K (172.XX.XX.1)
13-Jul-2018 12:49:49.445 query-errors: info: client @0x7f69407fa110 172.XX.XX.1#54377 (587-gc2.proxy.example.com): view vpn: query failed (SERVFAIL) for 587-gc2.proxy.example.com/IN/A at ../../../bin/named/query.c:6984
