ja *koennte*. gute router koennen es tatsaechlich - fuer einige zeit und solange die liste der gespeicherten adressen nicht zu lange wird. im normalfall (heim-user mit einzelrechner oder kleinnetzwerk oder kleines buero) fuehrt es nur dazu, dass die dns-anfrage zuerst an den router geschickt wird - dieser sie nicht beantworten kann und der dann erst eine anfrage an den nameserver beim provider schickt - es dauert also laenger.
wie barbakuss schon schrieb, cached auch windows dns-adressen, was man meistens erst bemerkt, wenn es sich eine falsche oder veraltete adresse hartnaeckig merkt - zu sehen mit ipconfig /displaydns
dies tipps mit dem lokalen cache / nameserver stammen aus zeiten, als wegen jeder dns-abfrage an den provider eine - kostenpflichtige - dial-up verbindung aufgemacht werden musste. aber wenn du im internet surfen willst, brauchst du ohnehin eine internet-verbindung.
sinnvoll ist ein lokaler dns-cache zb, wenn du ein intranet mit eigene servern im lan (firmennetz) hast oder auch, wenn du 50 oder 500 user hast, die alle pausenlos auf dieselben domains zugreifen. (zb du hast viele sekretaerinnen, die alle bahn- und flugverbindungen raussuschen muessen und deshalb 20mal am tag
www.oebb.at ansurfen oder alle deine user lesen in der mittagspause den online-standard)
fuer logfile-junkies ein ausschnitt aus dem log eines routers mit dem das tatsaechlich funktioniert:
- Code: Alles auswählen
Sep 16 07:00:14 192.168.0.254 INET: dnsd: qry from 127.0.0.1:10698 id 24370 "sip
.at43.at." A 1
Sep 16 07:00:14 192.168.0.254 INET: dnsd: cache 83.136.32.160 for sip.at43.at.
Sep 16 07:00:14 192.168.0.254 INET: dnsd: rsp to 127.0.0.1:10698 id 24370 "sip.a
t43.at." A 1/0/0
Sep 16 07:00:24 192.168.0.254 INET: dnsd: qry from 127.0.0.1:10698 id 24371 "p1.
voip.inode.at." A 1
Sep 16 07:00:24 192.168.0.254 INET: dnsd: cache 212.41.253.181 for p1.voip.inode
.at.
Sep 16 07:00:25 192.168.0.254 INET: dnsd: rsp to 127.0.0.1:10698 id 24371 "p1.vo
ip.inode.at." A 1/0/0
Sep 16 07:00:25 192.168.0.254 INET: dnsd: qry from 127.0.0.1:10698 id 24372 "p1.
voip.inode.at." 35 1
Sep 16 07:00:25 192.168.0.254 INET: dnsd: fwd 127.0.0.1:10698 id 24372 to 195.58
.160.194:53 id 28334 "p1.voip.inode.at." 35
Sep 16 07:00:25 192.168.0.254 INET: dnsd: rsp from 195.58.160.194:53 id 28334 "p
1.voip.inode.at." 35 0 0/1/0
Sep 16 07:00:25 192.168.0.254 INET: dnsd: rsp to 127.0.0.1:10698 id 24372 "p1.vo
ip.inode.at." 35 0/1/0
Sep 16 07:00:25 192.168.0.254 INET: dnsd: qry from 127.0.0.1:10698 id 24373 "_si
p._udp.p1.voip.inode.at." 33 1
Sep 16 07:00:25 192.168.0.254 INET: dnsd: cache neg for _sip._udp.p1.voip.inode.
at.
Sep 16 07:00:25 192.168.0.254 INET: dnsd: rsp to 127.0.0.1:10698 id 24373 "_sip.
_udp.p1.voip.inode.at." 33 0/0/0
Sep 16 07:00:25 192.168.0.254 INET: dnsd: qry from 127.0.0.1:10698 id 24374 "_si
p._tcp.p1.voip.inode.at." 33 1
Sep 16 07:00:26 192.168.0.254 INET: dnsd: cache neg for _sip._tcp.p1.voip.inode.
at.
Sep 16 07:00:26 192.168.0.254 INET: dnsd: rsp to 127.0.0.1:10698 id 24374 "_sip.
_tcp.p1.voip.inode.at." 33 0/0/0
Sep 16 07:00:26 192.168.0.254 INET: dnsd: qry from 127.0.0.1:10698 id 24375 "_si
ps._tcp.p1.voip.inode.at." 33 1
Sep 16 07:00:26 192.168.0.254 INET: dnsd: cache neg for _sips._tcp.p1.voip.inode
.at.
Sep 16 07:00:26 192.168.0.254 INET: dnsd: rsp to 127.0.0.1:10698 id 24375 "_sips
._tcp.p1.voip.inode.at." 33 0/0/0
Sep 16 07:03:13 192.168.0.254 INET: dnsd: qry from 127.0.0.1:10698 id 24376 "sip
.unet.univie.ac.at." A 1
Sep 16 07:03:13 192.168.0.254 INET: dnsd: rsp from 195.58.160.194:53 id 30692 "s
ip.unet.univie.ac.at." 35 0 0/1/0
Sep 16 07:03:13 192.168.0.254 INET: dnsd: rsp to 127.0.0.1:10698 id 24377 "sip.u
net.univie.ac.at." 35 0/1/0
Sep 16 07:03:13 192.168.0.254 INET: dnsd: qry from 127.0.0.1:10698 id 24378 "_si
p._udp.sip.unet.univie.ac.at." 33 1
Sep 16 07:03:13 192.168.0.254 INET: dnsd: fwd 127.0.0.1:10698 id 24378 to 195.58
.160.194:53 id 26639 "_sip._udp.sip.unet.univie.ac.at." 33
Sep 16 07:03:13 192.168.0.254 INET: dnsd: qry from 127.0.0.1:10698 id 24379 "_si
p._tcp.sip.unet.univie.ac.at." 33 1
Sep 16 07:03:13 192.168.0.254 INET: dnsd: cache neg for _sip._tcp.sip.unet.univi
e.ac.at.
Sep 16 07:03:14 192.168.0.254 INET: dnsd: rsp to 127.0.0.1:10698 id 24379 "_sip.
_tcp.sip.unet.univie.ac.at." 33 0/0/0
Sep 16 07:03:14 192.168.0.254 INET: dnsd: qry from 127.0.0.1:10698 id 24380 "_si
ps._tcp.sip.unet.univie.ac.at." 33 1
Sep 16 07:03:14 192.168.0.254 INET: dnsd: cache neg for _sips._tcp.sip.unet.univ
ie.ac.at.
Sep 16 07:03:14 192.168.0.254 INET: dnsd: rsp to 127.0.0.1:10698 id 24380 "_sips
._tcp.sip.unet.univie.ac.at." 33 0/0/0
Sep 16 07:03:14 192.168.0.254 INET: dnsd: rsp from 195.58.160.194:53 id 26639 "_
sip._udp.sip.unet.univie.ac.at." 33 0 1/0/1
Sep 16 07:03:14 192.168.0.254 INET: dnsd: rsp to 127.0.0.1:10698 id 24378 "_sip.
_udp.sip.unet.univie.ac.at." 33 1/0/1
Sep 16 07:03:14 192.168.0.254 INET: dnsd: qry from 127.0.0.1:10698 id 24381 "sip
.at43.at." A 1
Sep 16 07:03:14 192.168.0.254 INET: dnsd: fwd 127.0.0.1:10698 id 24381 to 195.58
.160.194:53 id 25491 "sip.at43.at." A
Sep 16 07:03:14 192.168.0.254 INET: dnsd: rsp from 195.58.160.194:53 id 25491 "s
ip.at43.at." A 0 1/0/0
Sep 16 07:03:15 192.168.0.254 INET: dnsd: cache add 83.136.32.160 for sip.at43.a
t.
Sep 16 07:03:15 192.168.0.254 INET: dnsd: rsp to 127.0.0.1:10698 id 24381 "sip.a
t43.at." A 1/0/0
Sep 16 07:03:25 192.168.0.254 INET: dnsd: qry from 127.0.0.1:10698 id 24382 "p1.
voip.inode.at." A 1
Sep 16 07:03:25 192.168.0.254 INET: dnsd: cache 212.41.253.181 for p1.voip.inode
.at.
Sep 16 07:03:25 192.168.0.254 INET: dnsd: rsp to 127.0.0.1:10698 id 24382 "p1.vo
ip.inode.at." A 1/0/0
Sep 16 07:03:25 192.168.0.254 INET: dnsd: qry from 127.0.0.1:10698 id 24383 "p1.
voip.inode.at." 35 1
Sep 16 07:03:25 192.168.0.254 INET: dnsd: fwd 127.0.0.1:10698 id 24383 to 195.58
.160.194:53 id 11726 "p1.voip.inode.at." 35
Sep 16 07:03:25 192.168.0.254 INET: dnsd: rsp from 195.58.160.194:53 id 11726 "p
1.voip.inode.at." 35 0 0/1/0
Sep 16 07:03:25 192.168.0.254 INET: dnsd: rsp to 127.0.0.1:10698 id 24383 "p1.vo
ip.inode.at." 35 0/1/0
Sep 16 07:03:25 192.168.0.254 INET: dnsd: qry from 127.0.0.1:10698 id 24384 "_si
p._udp.p1.voip.inode.at." 33 1
Sep 16 07:03:26 192.168.0.254 INET: dnsd: cache neg for _sip._udp.p1.voip.inode.
at.
Sep 16 07:03:26 192.168.0.254 INET: dnsd: rsp to 127.0.0.1:10698 id 24384 "_sip.
_udp.p1.voip.inode.at." 33 0/0/0
Sep 16 07:03:26 192.168.0.254 INET: dnsd: qry from 127.0.0.1:10698 id 24385 "_si
p._tcp.p1.voip.inode.at." 33 1
Sep 16 07:03:26 192.168.0.254 INET: dnsd: cache neg for _sip._tcp.p1.voip.inode.
at.
Sep 16 07:03:26 192.168.0.254 INET: dnsd: rsp to 127.0.0.1:10698 id 24385 "_sip.
_tcp.p1.voip.inode.at." 33 0/0/0
Sep 16 07:03:26 192.168.0.254 INET: dnsd: qry from 127.0.0.1:10698 id 24386 "_si
ps._tcp.p1.voip.inode.at." 33 1
Sep 16 07:03:26 192.168.0.254 INET: dnsd: cache neg for _sips._tcp.p1.voip.inode
.at.
Sep 16 07:03:26 192.168.0.254 INET: dnsd: rsp to 127.0.0.1:10698 id 24386 "_sips
._tcp.p1.voip.inode.at." 33 0/0/0
Sep 16 07:06:13 192.168.0.254 INET: dnsd: qry from 127.0.0.1:10698 id 24387 "sip
.unet.univie.ac.at." A 1
Sep 16 07:06:13 192.168.0.254 INET: dnsd: rsp to 127.0.0.1:10698 id 24387 "sip.u
net.univie.ac.at." A 1/0/0
Sep 16 07:06:13 192.168.0.254 INET: dnsd: qry from 127.0.0.1:10698 id 24388 "sip
.unet.univie.ac.at." 35 1
Sep 16 07:06:13 192.168.0.254 INET: dnsd: fwd 127.0.0.1:10698 id 24388 to 195.58
.160.194:53 id 13073 "sip.unet.univie.ac.at." 35
Sep 16 07:06:13 192.168.0.254 INET: dnsd: rsp from 195.58.160.194:53 id 13073 "s
ip.unet.univie.ac.at." 35 0 0/1/0
Sep 16 07:06:13 192.168.0.254 INET: dnsd: qry from 127.0.0.1:10698 id 24389 "_si
p._udp.sip.unet.univie.ac.at." 33 1
Sep 16 07:06:13 192.168.0.254 INET: dnsd: fwd 127.0.0.1:10698 id 24389 to 195.58
.160.194:53 id 9827 "_sip._udp.sip.unet.univie.ac.at." 33
Sep 16 07:06:13 192.168.0.254 INET: dnsd: qry from 127.0.0.1:10698 id 24390 "_si
p._tcp.sip.unet.univie.ac.at." 33 1
Sep 16 07:06:14 192.168.0.254 INET: dnsd: cache neg for _sip._tcp.sip.unet.univi
e.ac.at.
Sep 16 07:06:14 192.168.0.254 INET: dnsd: rsp to 127.0.0.1:10698 id 24390 "_sip.
_tcp.sip.unet.univie.ac.at." 33 0/0/0
Sep 16 07:06:14 192.168.0.254 INET: dnsd: qry from 127.0.0.1:10698 id 24391 "_si
ps._tcp.sip.unet.univie.ac.at." 33 1
Sep 16 07:06:14 192.168.0.254 INET: dnsd: cache neg for _sips._tcp.sip.unet.univ
ie.ac.at.
Sep 16 07:06:14 192.168.0.254 INET: dnsd: rsp to 127.0.0.1:10698 id 24391 "_sips
._tcp.sip.unet.univie.ac.at." 33 0/0/0
Sep 16 07:06:14 192.168.0.254 INET: dnsd: rsp from 195.58.160.194:53 id 9827 "_s
ip._udp.sip.unet.univie.ac.at." 33 0 1/0/1
Sep 16 07:06:14 192.168.0.254 INET: dnsd: rsp to 127.0.0.1:10698 id 24389 "_sip.
_udp.sip.unet.univie.ac.at." 33 1/0/1
Sep 16 07:06:14 192.168.0.254 INET: dnsd: qry from 127.0.0.1:10698 id 24392 "sip
.at43.at." A 1
Sep 16 07:06:14 192.168.0.254 INET: dnsd: cache 83.136.32.160 for sip.at43.at.
Sep 16 07:06:14 192.168.0.254 INET: dnsd: rsp to 127.0.0.1:10698 id 24392 "sip.a
t43.at." A 1/0/0
Sep 16 07:06:24 192.168.0.254 INET: dnsd: qry from 127.0.0.1:10698 id 24393 "p1.
voip.inode.at." A 1
Sep 16 07:06:25 192.168.0.254 INET: dnsd: cache 212.41.253.181 for p1.voip.inode
.at.
Sep 16 07:06:25 192.168.0.254 INET: dnsd: rsp to 127.0.0.1:10698 id 24393 "p1.vo
ip.inode.at." A 1/0/0
Sep 16 07:06:25 192.168.0.254 INET: dnsd: qry from 127.0.0.1:10698 id 24394 "p1.
voip.inode.at." 35 1
Sep 16 07:06:25 192.168.0.254 INET: dnsd: fwd 127.0.0.1:10698 id 24394 to 195.58
.160.194:53 id 20081 "p1.voip.inode.at." 35
Sep 16 07:06:25 192.168.0.254 INET: dnsd: rsp from 195.58.160.194:53 id 20081 "p
1.voip.inode.at." 35 0 0/1/0
Sep 16 07:06:25 192.168.0.254 INET: dnsd: rsp to 127.0.0.1:10698 id 24394 "p1.vo
ip.inode.at." 35 0/1/0
Sep 16 07:06:25 192.168.0.254 INET: dnsd: qry from 127.0.0.1:10698 id 24395 "_si
p._udp.p1.voip.inode.at." 33 1
Sep 16 07:06:25 192.168.0.254 INET: dnsd: cache neg for _sip._udp.p1.voip.inode.
at.
Sep 16 07:06:25 192.168.0.254 INET: dnsd: rsp to 127.0.0.1:10698 id 24395 "_sip.
_udp.p1.voip.inode.at." 33 0/0/0
Sep 16 07:06:26 192.168.0.254 INET: dnsd: qry from 127.0.0.1:10698 id 24396 "_si
p._tcp.p1.voip.inode.at." 33 1
Sep 16 07:06:26 192.168.0.254 INET: dnsd: cache neg for _sip._tcp.p1.voip.inode.
at.
Sep 16 07:06:26 192.168.0.254 INET: dnsd: rsp to 127.0.0.1:10698 id 24396 "_sip.
_tcp.p1.voip.inode.at." 33 0/0/0
Sep 16 07:06:26 192.168.0.254 INET: dnsd: qry from 127.0.0.1:10698 id 24397 "_si
ps._tcp.p1.voip.inode.at." 33 1
Sep 16 07:06:26 192.168.0.254 INET: dnsd: cache neg for _sips._tcp.p1.voip.inode
.at.
Sep 16 07:06:26 192.168.0.254 INET: dnsd: rsp to 127.0.0.1:10698 id 24397 "_sips
._tcp.p1.voip.inode.at." 33 0/0/0
Sep 16 07:09:13 192.168.0.254 INET: dnsd: qry from 127.0.0.1:10698 id 24398 "sip
.unet.univie.ac.at." A 1
Sep 16 07:09:13 192.168.0.254 INET: dnsd: rsp from 195.58.160.194:53 id 26226 "s
ip.unet.univie.ac.at." 35 0 0/1/0
Sep 16 07:09:13 192.168.0.254 INET: dnsd: rsp to 127.0.0.1:10698 id 24399 "sip.u
net.univie.ac.at." 35 0/1/0
Sep 16 07:09:13 192.168.0.254 INET: dnsd: qry from 127.0.0.1:10698 id 24400 "_si
p._udp.sip.unet.univie.ac.at." 33 1
Sep 16 07:09:13 192.168.0.254 INET: dnsd: fwd 127.0.0.1:10698 id 24400 to 195.58
.160.194:53 id 21969 "_sip._udp.sip.unet.univie.ac.at." 33
Sep 16 07:09:13 192.168.0.254 INET: dnsd: qry from 127.0.0.1:10698 id 24401 "_si
p._tcp.sip.unet.univie.ac.at." 33 1
Sep 16 07:09:13 192.168.0.254 INET: dnsd: cache neg for _sip._tcp.sip.unet.univi
e.ac.at.
Sep 16 07:09:14 192.168.0.254 INET: dnsd: rsp to 127.0.0.1:10698 id 24401 "_sip.
_tcp.sip.unet.univie.ac.at." 33 0/0/0
Sep 16 07:09:14 192.168.0.254 INET: dnsd: qry from 127.0.0.1:10698 id 24402 "_si
ps._tcp.sip.unet.univie.ac.at." 33 1
Sep 16 07:09:14 192.168.0.254 INET: dnsd: cache neg for _sips._tcp.sip.unet.univ
ie.ac.at.
Sep 16 07:09:14 192.168.0.254 INET: dnsd: rsp to 127.0.0.1:10698 id 24402 "_sips
._tcp.sip.unet.univie.ac.at." 33 0/0/0
Sep 16 07:09:14 192.168.0.254 INET: dnsd: rsp from 195.58.160.194:53 id 21969 "_
sip._udp.sip.unet.univie.ac.at." 33 0 1/0/1
Sep 16 07:09:14 192.168.0.254 INET: dnsd: rsp to 127.0.0.1:10698 id 24400 "_sip.
_udp.sip.unet.univie.ac.at." 33 1/0/1
Sep 16 07:09:14 192.168.0.254 INET: dnsd: qry from 127.0.0.1:10698 id 24403 "sip
.at43.at." A 1
Sep 16 07:09:14 192.168.0.254 INET: dnsd: fwd 127.0.0.1:10698 id 24403 to 195.58
.160.194:53 id 19675 "sip.at43.at." A
Sep 16 07:09:14 192.168.0.254 INET: dnsd: rsp from 195.58.160.194:53 id 19675 "s
ip.at43.at." A 0 1/0/0
Sep 16 07:09:15 192.168.0.254 INET: dnsd: cache add 83.136.32.160 for sip.at43.a
t.
Sep 16 07:09:15 192.168.0.254 INET: dnsd: rsp to 127.0.0.1:10698 id 24403 "sip.a
t43.at." A 1/0/0
Sep 16 07:09:25 192.168.0.254 INET: dnsd: qry from 127.0.0.1:10698 id 24404 "p1.
voip.inode.at." A 1
Sep 16 07:09:25 192.168.0.254 INET: dnsd: cache 212.41.253.181 for p1.voip.inode
.at.
Sep 16 07:09:25 192.168.0.254 INET: dnsd: rsp to 127.0.0.1:10698 id 24404 "p1.vo
ip.inode.at." A 1/0/0
Sep 16 07:09:25 192.168.0.254 INET: dnsd: qry from 127.0.0.1:10698 id 24405 "p1.
voip.inode.at." 35 1
Sep 16 07:09:25 192.168.0.254 INET: dnsd: fwd 127.0.0.1:10698 id 24405 to 195.58
.160.194:53 id 16543 "p1.voip.inode.at." 35
Sep 16 07:09:25 192.168.0.254 INET: dnsd: rsp from 195.58.160.194:53 id 16543 "p
1.voip.inode.at." 35 0 0/1/0
Sep 16 07:09:25 192.168.0.254 INET: dnsd: rsp to 127.0.0.1:10698 id 24405 "p1.vo
ip.inode.at." 35 0/1/0