Bind 9 Administrator Reference Manual

Chapter 6. BIND 9 Conﬁguration Reference

If you discover that a remote server is giving out bad data, marking it as bogus will prevent further

queries to it. The default value of bogus is no.

The provide-ixfr clause determines whether the local server, acting as master, will respond with an

incremental zone transfer when the given remote server, a slave, requests it. If set to yes, incremental

transfer will be provided whenever possible. If set to no, all transfers to the remote server will be

nonincremental. If not set, the value of the provide-ixfr option in the view or global options block is

used as a default.

The request-ixfr clause determines whether the local server, acting as a slave, will request incremental

zone transfers from the given remote server, a master. If not set, the value of the request-ixfr option in

the view or global options block is used as a default.

IXFR requests to servers that do not support IXFR will automatically fall back to AXFR. Therefore,

there is no need to manually list which servers support IXFR and which ones do not; the global default of

yes should always work. The purpose of the provide-ixfr and request-ixfr clauses is to make it possible

to disable the use of IXFR even when both master and slave claim to support it, for example if one of the

servers is buggy and crashes or corrupts data when IXFR is used.

The edns clause determines whether the local server will attempt to use EDNS when communicating

with the remote server. The default is yes.

The server supports two zone transfer methods. The ﬁrst, one-answer, uses one DNS message per

resource record transferred. many-answers packs as many resource records as possible into a message.

many-answers is more efﬁcient, but is only known to be understood by BIND 9, BIND 8.x, and patched

versions of BIND 4.9.5. You can specify which method to use for a server with the transfer-format

option. If transfer-format is not speciﬁed, the transfer-format speciﬁed by the options statement will

be used.

transfers is used to limit the number of concurrent inbound zone transfers from the speciﬁed server. If

no transfers clause is speciﬁed, the limit is set according to the transfers-per-ns option.

The keys clause is used to identify a key_id deﬁned by the key statement, to be used for transaction

security when talking to the remote server. The key statement must come before the server statement

that references it. When a request is sent to the remote server, a request signature will be generated using

the key speciﬁed here and appended to the message. A request originating from the remote server is not

required to be signed by this key.

Although the grammar of the keys clause allows for multiple keys, only a single key per server is

currently supported.

6.2.17. trusted-keys Statement Grammar

trusted-keys {