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could anyone explain the behaviour of DNS slave.

i am testing dns server, for internal purpose, and after configuring master slave everything works fine, but i am willing to understand the mechanism behind,

lets say, and[my 2 dns]

however, i wanted to make dnsslave to be available to serve query if is down. [well it works until now]

having said that, i want to update records on [while is down]. i can resolve things from dns slave but turning off master and updating records, but not until i restart

So, is this something caused by, expiry time on soa?

                            43200      ; refresh (12 hours)
            900        ; retry (15 minutes)
            1209600    ; expire (2 weeks)
            300        ; minimum (5 minutes)

EDIT: I know what is the purpose of DNS master and slave, i am talking while dnsmaster is down, slave is only in use and i need to update A record. [at this condition dns doesn't work with reload it only works on restart, so anyone with better knowledge and experience please share your view.]

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What? How are you changing records on the slave while the master is down? – faker Sep 16 '13 at 20:17
If you are using standard replication, then you shouldn't be editing a slave. DNS is a single master replication system. If the master is failed, you pick a new master and update settings so that it will be come the master. If you don't want that behavior, you have to use some external tool for replication, or a DNS server other then Bind. – Zoredache Sep 16 '13 at 20:34
well, that is the thing i am trying to solve, if dnsmaster is down, and i have only slave and assuming that i need to update A record. I will be updating slave. This is not an problem, and no wojciech you are wrong, you can update slave and treat it as master. I think answer are not what i am trying to know, i am willing to know what deny's slave not to serve until restart – tike Sep 16 '13 at 21:12

Slave nameserver updates its data from master by zone transfer. When master is down, slave can only serve what it transferred from master earlier.

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