DNS on Pace router

[Guest]

Has anyone noticed if letting their Pace router (the one provided by Sonic) serve DHCP and hand out its own address for DNS introduces a slight lag in web browsing? I noticed that if I forced my operating system to use 208.201.224.11 rather than the router, pages start to load faster. When using the router for DNS there would be about a half second delay from clicking a link to actual data transfer.

I'm using Windows. Is anyone seeing the same behavior?

[digitalbitstream]

Benchmark it and report back! https://www.grc.com/dns/benchmark.htm

[jamesbai]

Actually yes, I noticed the same since moving service to a new location and switching to the Pace router. I was finally getting around to setting up my own Linux router as a replacement because I got frustrated with this subtle/intermittent issue, when I discovered something somewhat surprising...from my experimentation, it seems that if the Pace router's DNS server receives a new request while another request is already being processed, it delays the new lookup by exactly 1 second. This can cause enormous delays if you're doing something which looks up many hosts at once, and noticeably affects the snappiness of web browsing.

Here are the tests I ran to come to this conclusion. This line of shell code launches 10 background dns lookups simultaneously, and times how long it takes for them all to finish.

Reverse resolve 10 hosts simultaneously, using Pace router's DNS server:

Code: Select all

$ time sh -c 'for I in `seq 8 17`; do sh -c "host 64.124.148.$I 192.168.42.1 >/dev/null && echo -n ." & done; wait'
.........
real    0m10.019s
user    0m0.088s
sys     0m0.028s

Reverse resolve 10 hosts simultaneously, using Google's DNS servers:

Code: Select all

$ time sh -c 'for I in `seq 8 17`; do sh -c "host 64.124.148.$I 8.8.8.8 >/dev/null && echo -n ." & done; wait'
..........
real    0m0.071s
user    0m0.064s
sys     0m0.036s

Interestingly, if I run it synchronously (without backgrounding processes - replaced & with ; ) it runs significantly faster:

Code: Select all

$ time sh -c 'for I in `seq 8 17`; do sh -c "host 64.124.148.$I 192.168.42.1 >/dev/null && echo -n ." ; done; wait'
..........
real    0m0.421s
user    0m0.052s
sys     0m0.036s

I suspect there are some serious flaws in the DNS server implementation on these devices. Anyone who's seeing slowness while using the Pace router should seriously considering switching to 8.8.8.8 or some other free DNS provider until this is looked into.

[digitalbitstream]

I'm not sure the flaw is in the pace. I see the 1 second delay through a different brand of router. Direct to 208.201.224.11 or 8.8.8.8 is fast (tenth of a second). Going through the default setup I get delays of 1.008 seconds on both the shell script above, and DNSBench.

[digitalbitstream]

The results are not even close. 192.168.2.1 is the router. The others bypass the router:

Domain Name Server Benchmark_18.png (43.71 KiB) Viewed 4814 times

For a web page coming from a variety of hosts, a 1.0008 second DNS delay could be significant.

Namebench shows the same thing:

Mean response (in milliseconds):
--------------------------------
SYS-208.201.224. ########### 78.21
Google Public DNS ############## 93.83
Qwest-2 US ############## 94.82
DynGuide ################# 115.69
UltraDNS ####################### 158.20
Internal 192-168 ##################################################### 377.34