I am trying to figure out why my Santa Cruz mountains Surfnet WISP setup
takes so long to load a web page (even Google's bare bones home page
takes, sometimes far too long) so I'm trying to better understand how DNS
servers work.
What I have in my wrt54g home router is a set of three supposedly fast DNS
servers from this DNS server list:
http://theos.in/windows-xp/free-fast...ns-server-list
But, even so, on multiple computers in the home, Linux & Windoze, it
takes far too long to 'get' the web pages, even though speedtest.net
shows 18ms ping latency, 1Mbps upload, & 1.2 Mbps download.
I keep getting intermittent "Microtik hotspot errors" from Surfnet ...
and their (rather grouchy) technical support blamed my DNS servers setup.
I can't prove or disprove that until/unless I better understand DNS
servers, overall, and how they impact speed of loading (or not loading)
web pages.
Is 'this' what happens?
1. I type
www.google.com in my laptop browser on PC 10.20.30.1
2. That "www.google.com" request goes wirelessly to my office wrt54g
router which is 10.20.30.40
THIS IS THE PART THAT I 'THINK' I UNDERSTAND ...
3. The office wrt54g router sends that "www.google.com" request to the
rooftop ubuquiti radio which is 192.168.10.20 but the office wrt54g
router must also be sending its DNS server list to the bridge (right?)
a) wrt54g DNS1 = 8.8.8.8
b) wrt54g DNS2 = 8.8.4.4
c) wrt54g DNS3 = 4.2.2.1
d) wrt54g WINS = blank
What command can I use to 'see' that DNS transaction?
4. My rooftop ubiquiti radio sends the "www.google.com" request & DNS
list to my rooftop antenna which sends it through the air to the Surfnet
line-of-sight antenna on 192.168.4.1
THIS IS THE PART I REALLY DON'T UNDERSTAND.
5. Surfnet sees that request for "www.google.com" and the list of three
DNS servers (I guess), and it forwards that "www.google.com" request to
the first of those DNS servers (I guess) which is 8.8.8.8.
6. The DNS server at 8.8.8.8 presumably forwards back the IP address of
"www.google.com" (e.g., 74.125.224.112) but a "traceroute www.google.com"
on Ubuntu doesn't seem to show any of that).
HOW DO I CHECK HOW LONG THE DNS SERVER IS TAKING TO RESPOND?
Here is a traceroute:
$ traceroute
www.google.com
traceroute to
www.google.com (74.125.224.112), 30 hops max, 60 byte
packets
1 10.20.30.40 (10.20.30.40) 2.587 ms 7.338 ms 7.903 ms
2 192.168.10.20 (192.168.10.20) 16.803 ms 17.272 ms 17.713 ms
3 192.168.4.1 (192.168.4.1) 20.221 ms 20.353 ms 20.523 ms
4 64.74.213.61 (64.74.213.61) 20.618 ms 20.837 ms 21.409 ms
5 sanjose-mk.surfnetc.com (64.74.213.193) 23.447 ms 23.628 ms 23.856
ms
6 border1.internap.surfnetc.com (66.151.140.1) 24.043 ms 5.466 ms
15.656 ms
7 border1.g6-3.surfcomm-3.sje003.pnap.net (64.95.143.165) 16.140 ms
16.763 ms 17.040 ms
8 core3.pc1-bbnet1.sje.pnap.net (66.151.144.3) 17.494 ms core3.pc2-
bbnet2.sje.pnap.net (66.151.144.67) 21.470 ms core3.pc1-
bbnet1.sje.pnap.net (66.151.144.3) 21.654 ms
9 xe-0-0-0-4.r06.snjsca04.us.bb.gin.ntt.net (128.241.219.129) 21.791
ms 21.941 ms 22.055 ms
10 ae-3.r07.snjsca04.us.bb.gin.ntt.net (129.250.5.59) 22.256 ms 25.348
ms 27.017 ms
11 xe-9-0-0.edge1.sanjose3.level3.net (4.68.110.49) 26.147 ms * 27.038
ms
12 * * *
13 you-tube-in.edge2.sanjose1.level3.net (4.79.40.178) 13.144 ms
13.649 ms 17.372 ms
14 72.14.232.136 (72.14.232.136) 17.558 ms 17.943 ms 18.496 ms
15 64.233.174.109 (64.233.174.109) 18.914 ms 26.702 ms 24.631 ms
16 74.125.224.112 (74.125.224.112) 26.859 ms 27.346 ms 27.018 ms
Obviously I'm confused but I'm trying to debug why web pages,
intermittently, take far too long to load (and one out of fifty fail
outright, giving a Microtik hotspot error, 192.168.4.1).
Is there a command that shows what is happening at the DNS server level?