[Gennadi]

Принимаем, что локальная сеть1 - 80.91.197.0/24
ip adress DNS1 80.91.197.1

ip adress DNS2 80.91.197.100 ( напишешь ip aderess твоего DNS2)

named.conf для DNS1 - Master DNS
##################################
options {
directory "/var/named";
recursion yes;
allow-query { 80.91.197.0/24; 127.0.0/8; };
allow-transfer { 80.91.197.100; }; # DNS2 - Slave DNS
transfer-format many-answers;
forward first ;
forwarders { 194.25.2.129; 195.20.224.234; }; # DNS'ы провайдера
listen-on port 53 { 80.91.197.1; };
allow-recursion { 80.91.197.0/24; localhost; };
};

zone "." IN {
type hint;
file "named.ca";
};

zone "localhost" IN {
type master;
file "localhost.zone";
allow-update { none; };
};

zone "0.0.127.in-addr.arpa" IN {
type master;
file "named.local";
allow-update { none; };
};

zone "domain.ru" IN {
type master;
file "domain.host";
allow-update { none; };
notify yes;
also-notify { 80.91.197.1; };
};

zone "197.91.80.in-addr.arpa" IN {
type master;
file "197.91.80.ARPA";
allow-update { none; };
notify yes;
also-notify { 80.91.197.1; };
};


include "/etc/rndc.key";
######################################


named.conf для DNS2 - Slave DNS
###############################
options {
directory "/var/named";
recursion no;
allow-query { 80.91.197.0/24; 127.0.0/8; };
allow-transfer { 80.91.197.1; };
transfer-format many-answers;
notify no;
};

include "/etc/rndc.key";

zone "." IN {
type hint;
file "named.ca";
};

zone "localhost" IN {
type master;
file "localhost.zone";
allow-update { none; };
};

zone "0.0.127.in-addr.arpa" IN {
type master;
file "named.local";
allow-update { none; };
};

zone "domain.ru" IN {
type slave;
file "domain.host";
masters { 80.91.197.1; };
};

zone "197.91.80.in-addr.arpa" IN {
type slave;
file "197.91.80.ARPA";
masters { 80.91.197.1; };
};
##################################

После restart'a обоих DNS'ов в директории /var/named на втором DNS'е, появяться два файла:

"domain.host" и "197.91.80.ARPA".

см. /var/log/messages

Примечание: При изменениях в файлах "domain.host" и "197.91.80.ARPA" на DNS1-Master DNS, update DNS2 - Slave DNS будет происходить только в том случае, если serial (число) будет увеличен.