linux下安装dns本地缓存
linux的版本是gentoo
写爬虫不用dns缓存很容易就
Error:6 - Couldn't resolve host 'rss.news.yahoo.com'
装一个缓存也很简单 摘抄如下 赞美D前辈
http://electrostorm.net/archive/2007/10/enabling-dns-cache-dnsmasq-gentoo
""""
# emerge -av dnsmasq
Then insert 'nameserver 127.0.0.1' into the first (important!) line in /etc/resolv.conf
nameserver 127.0.0.1
...
Then start dnsmasq
# /etc/init.d/dnsmasq start
You can test your local DNS cache by typing 这个工具在bind-tools中
dig google.de
Have a look at the query time (must be something higher than 50ms in most cases). Query google again.
Now that's amazing, isn't it? 0msec!
Let dnsmasq start at boot (otherwise you can't resolve any DNS names because you've edited the /etc/resolv.conf)
# rc-update add dnsmasq default
""""
~ $ sudo dig blogbus.com
; <<>> DiG 9.4.2-P2 <<>> blogbus.com
;; global options: printcmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 38631
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 2, ADDITIONAL: 8
;; QUESTION SECTION:
;blogbus.com.INA
;; ANSWER SECTION:
blogbus.com.3600INA210.51.44.249
;; AUTHORITY SECTION:
blogbus.com.78INNSns1.dns.com.cn.
blogbus.com.78INNSns2.dns.com.cn.
;; ADDITIONAL SECTION:
ns1.dns.com.cn.667INA124.42.122.8
ns1.dns.com.cn.667INA124.42.122.9
ns1.dns.com.cn.667INA122.70.138.5
ns1.dns.com.cn.667INA122.70.138.6
ns2.dns.com.cn.2477INA124.42.122.6
ns2.dns.com.cn.2477INA122.70.138.8
ns2.dns.com.cn.2477INA122.70.138.9
ns2.dns.com.cn.2477INA124.42.122.5
;; Query time: 9 msec
;; SERVER: 127.0.0.1#53(127.0.0.1)
;; WHEN: Sun Apr 12 11:56:16 2009
;; MSG SIZE rcvd: 219
~ $ sudo dig blogbus.com
; <<>> DiG 9.4.2-P2 <<>> blogbus.com
;; global options: printcmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 2017
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 0
;; QUESTION SECTION:
;blogbus.com.INA
;; ANSWER SECTION:
blogbus.com.3597INA210.51.44.249
;; Query time: 0 msec
;; SERVER: 127.0.0.1#53(127.0.0.1)
;; WHEN: Sun Apr 12 11:56:19 2009
;; MSG SIZE rcvd: 45
~ $ sudo dig rss.news.yahoo.com
; <<>> DiG 9.4.2-P2 <<>> rss.news.yahoo.com
;; global options: printcmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 13933
;; flags: qr rd ra; QUERY: 1, ANSWER: 3, AUTHORITY: 3, ADDITIONAL: 3
;; QUESTION SECTION:
;rss.news.yahoo.com.INA
;; ANSWER SECTION:
rss.news.yahoo.com.300INCNAMEgeoycs-p.gy1.b.yahoodns.net.
geoycs-p.gy1.b.yahoodns.net. 1476 INCNAMEl1.ycs.glb.cn.yahoo.com.
l1.ycs.glb.cn.yahoo.com. 186INA203.209.246.249
;; AUTHORITY SECTION:
glb.cn.yahoo.com.1853INNSgtm1.glb.cnh.yahoo.com.
glb.cn.yahoo.com.1853INNSgtm1.glb.cn2.yahoo.com.
glb.cn.yahoo.com.1853INNSgtm1.glb.cnb.yahoo.com.
;; ADDITIONAL SECTION:
gtm1.glb.cn2.yahoo.com.6692INA202.160.176.148
gtm1.glb.cnb.yahoo.com.1651INA202.165.98.16
gtm1.glb.cnh.yahoo.com.6692INA203.209.251.160
;; Query time: 7 msec
;; SERVER: 127.0.0.1#53(127.0.0.1)
;; WHEN: Sun Apr 12 11:58:49 2009
;; MSG SIZE rcvd: 250
~ $ sudo dig rss.news.yahoo.com
; <<>> DiG 9.4.2-P2 <<>> rss.news.yahoo.com
;; global options: printcmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 32314
;; flags: qr rd ra; QUERY: 1, ANSWER: 3, AUTHORITY: 0, ADDITIONAL: 0
;; QUESTION SECTION:
;rss.news.yahoo.com.INA
;; ANSWER SECTION:
rss.news.yahoo.com.298INCNAMEgeoycs-p.gy1.b.yahoodns.net.
geoycs-p.gy1.b.yahoodns.net. 1474 INCNAMEl1.ycs.glb.cn.yahoo.com.
l1.ycs.glb.cn.yahoo.com. 184INA203.209.246.249
;; Query time: 0 msec
;; SERVER: 127.0.0.1#53(127.0.0.1)
;; WHEN: Sun Apr 12 11:58:51 2009
;; MSG SIZE rcvd: 130
