[hcoop/zz_old/debian/djbdns.git] / debian / djbdns-man / axfr-get.8

.TH axfr-get 8

.SH NAME
axfr-get \- a DNS zone-transfer client.

It sends a zone-transfer request
in DNS-over-TCP format to descriptor 7,
reads the results from descriptor 6,
and saves the results in a file.

.SH SYNOPSIS
Normally 
.B axfr-get
is run under 
.BR tcpclient (1),
which sets up descriptors 6 and 7 as a TCP connection to a remote host.

.B axfr-get 
.I z
.I fn
.I fn.tmp

.SH DESCRIPTION
.B axfr-get
performs a zone transfer for domain 
.IR z .
It writes the results to 
.I fn.tmp
in a format that can be used as input to
.BR tinydns-data (8).
If the zone transfer completes successfully,
.B axfr-get
atomically renames 
.I fn.tmp
as 
.IR fn .

.I fn.tmp
and 
.I fn
must be on the same filesystem.

.B axfr-get
writes the zone serial number as a comment at the top of
.IR fn.tmp .
It skips the zone transfer,
leaving 
.I fn
alone,
if
.I fn
already exists,
 
.I fn
has a serial number
matching the zone serial number,
and both serial numbers are nonzero.

Zone transfers often include duplicate records.
You should feed the 
.B axfr-get
results through
sort -u.

.B axfr-get
discards all records outside the domain 
.IR z .
It accepts records in child zones,
but it marks all child zones as non-authoritative, so
.BR tinydns (8)
will not report those records except as glue.
If you plan to merge the 
.B axfr-get
results
for a domain and a child of the same domain,
creating a file authoritative for both zones,
make sure to eliminate records in the first output
that are within the child zone.

.B axfr-get
will accept arbitrarily large zone transfers.
To limit the maximum file size to 1 megabyte,
run 
.B axfr-get
under 
.BR softlimit 
\-f 1048576.

.SH Compatibility notes

.B axfr-get
handles
BIND's RFC-1034-violating multiple-answers zone-transfer format.

.B axfr-get
does not precisely simulate BIND's handling of 
.IR *.dom .
Under BIND, records for
.I *.dom
do not apply to
.I y.dom
or
.I anything.y.dom
if there is a normal record for
.IR x.y.dom .
With 
.B axfr-get
and 
.BR tinydns (8),
the records apply to 
.I y.dom
and
.I anything.y.dom
except 
.IR x.y.dom .

.B axfr-get
does not precisely simulate BIND's handling of multiple IP addresses
for a single name.
When there are more than 8 addresses,
.BR tinydns (8)
selects a random set of 8 for each query.

.SH SEE ALSO
axfrdns(8),
tinydns(8),
tinydns-data(8),
tcpclient(1),
softlimit(8)
http://cr.yp.to/djbdns.html
Commit	Line	Data
b4588d5c GP	1	.TH axfr-get 8
	2
	3	.SH NAME
	4	axfr-get \- a DNS zone-transfer client.
	5
	6	It sends a zone-transfer request
	7	in DNS-over-TCP format to descriptor 7,
	8	reads the results from descriptor 6,
	9	and saves the results in a file.
	10
	11	.SH SYNOPSIS
	12	Normally
	13	.B axfr-get
	14	is run under
	15	.BR tcpclient (1),
	16	which sets up descriptors 6 and 7 as a TCP connection to a remote host.
	17
	18	.B axfr-get
	19	.I z
	20	.I fn
	21	.I fn.tmp
	22
	23	.SH DESCRIPTION
	24	.B axfr-get
	25	performs a zone transfer for domain
	26	.IR z .
	27	It writes the results to
	28	.I fn.tmp
	29	in a format that can be used as input to
	30	.BR tinydns-data (8).
	31	If the zone transfer completes successfully,
	32	.B axfr-get
	33	atomically renames
	34	.I fn.tmp
	35	as
	36	.IR fn .
	37
	38	.I fn.tmp
	39	and
	40	.I fn
	41	must be on the same filesystem.
	42
	43	.B axfr-get
	44	writes the zone serial number as a comment at the top of
	45	.IR fn.tmp .
	46	It skips the zone transfer,
	47	leaving
	48	.I fn
	49	alone,
	50	if
	51	.I fn
	52	already exists,
	53
	54	.I fn
	55	has a serial number
	56	matching the zone serial number,
	57	and both serial numbers are nonzero.
	58
	59	Zone transfers often include duplicate records.
	60	You should feed the
	61	.B axfr-get
	62	results through
	63	sort -u.
	64
65	.B axfr-get
66	discards all records outside the domain
67	.IR z .
68	It accepts records in child zones,
69	but it marks all child zones as non-authoritative, so
70	.BR tinydns (8)
71	will not report those records except as glue.
72	If you plan to merge the
73	.B axfr-get
74	results
75	for a domain and a child of the same domain,
76	creating a file authoritative for both zones,
77	make sure to eliminate records in the first output
78	that are within the child zone.
79
80	.B axfr-get
81	will accept arbitrarily large zone transfers.
82	To limit the maximum file size to 1 megabyte,
83	run
84	.B axfr-get
85	under
86	.BR softlimit
87	\-f 1048576.
88
89	.SH Compatibility notes
90
91	.B axfr-get
92	handles
93	BIND's RFC-1034-violating multiple-answers zone-transfer format.
94
95	.B axfr-get
96	does not precisely simulate BIND's handling of
97	.IR *.dom .
98	Under BIND, records for
99	.I *.dom
100	do not apply to
101	.I y.dom
102	or
103	.I anything.y.dom
104	if there is a normal record for
105	.IR x.y.dom .
106	With
107	.B axfr-get
108	and
109	.BR tinydns (8),
110	the records apply to
111	.I y.dom
112	and
113	.I anything.y.dom
114	except
115	.IR x.y.dom .
116
117	.B axfr-get
118	does not precisely simulate BIND's handling of multiple IP addresses
119	for a single name.
120	When there are more than 8 addresses,
121	.BR tinydns (8)
122	selects a random set of 8 for each query.
123
124	.SH SEE ALSO
125	axfrdns(8),
126	tinydns(8),
127	tinydns-data(8),
128	tcpclient(1),
129	softlimit(8)
130	http://cr.yp.to/djbdns.html