If it is necessary for a secondary nameserver to receive zone data
via zone transfer from the primary server, follow the instructions here. Use
dnssec-keygen to create a symmetric key file in the current directory:
$ cd /tmp
$ sudo dnssec-keygen -a HMAC-MD5 -b 128 -n HOST dns.example.com
Kdns.example.com .+aaa +iiiii
This output is the name of a file containing the new key. Read the file to find
the base64-encoded key string:
$ sudo cat Kdns.example.com .+NNN +MMMMM .key
dns.example.com IN KEY 512 3 157 base64-key-string
Add the directives to /etc/named.conf on the primary server:
key zone-transfer-key {
algorithm hmac-md5;
secret "base64-key-string ";
};
zone "example.com " IN {
type master;
allow-transfer { key zone-transfer-key; };
...
};
Add the directives below to /etc/named.conf on the secondary nameserver:
key zone-transfer-key {
algorithm hmac-md5;
secret "base64-key-string ";
};
server IP-OF-MASTER {
keys { zone-transfer-key; };
};
zone "example.com " IN {
type slave;
masters { IP-OF-MASTER ; };
...
};