Macintosh

[UHFhd]

Server not found

Firefox can't find the server at newlondon.craigslist.org.

 using net monitor side kick i can see the repeated dns requests would the problem be with comcast nodes or craigslist server ?

[EG]

Does thes link work ?

http://208.82.236.129

[UHFhd]

yes that link worked

[UHFhd]

i would prefer not to have to use network utility , lookup ip to get to the craigslist though, am using 75.75.75.75 for comcast dns

[EG]

That is one of their new DNSSec anycast servers and there have been some known problems with the resolving of some domains. Just for the halibut, have you tried flushing your DNS cache ?

[UHFhd]

int3resting the first ip you posted brought me to cap cod craigslist 

 i used network utility lookup entered newlondon.craigslist.org got the same ip u posted 

 i tryed that test of same ip again and got hartford.craigslist.org  

[UHFhd]

yes i flushed the dns cache 2 days ago using terminal commands

[EG]

I am going to make a Comcast employee that oversees their DNS aware of your issue.

[UHFhd]

Thank you hope it helps other macintosh users also 

[EG]

Maybe you could use one of their alternate DNS servers in the interim or use the OpenDNS or the Google offerings.

[UHFhd]

ty will give google dns a try 

[EG]

I'm pretty sure that they are going to want to see a trace route to 75.75.75.75 from you.  

[UHFhd]

next time there is time out in progress  i'll do a trace root to comcast dns server and save results in meantime i will switch back to the comcast dns server so i can get those results

[EG]

They just want to see which DNS server farm/cluster that you are being pointed to with that address.

[UHFhd]

post here ?  - ip address

[EG]

Yes. Post the results of a trace to 75.75.75.75 here in your thread please.

[UHFhd]

traceroute to 75.75.75.75 (75.75.75.75), 64 hops max, 40 byte packets

 1 Removed ip   9.521 ms  2.559 ms  2.976 ms

 2  73.158.64.1 (73.158.64.1)  11.916 ms  8.677 ms  10.000 ms

 3  ge-3-37-ur01.********.ct.hartford.comcast.net (68.87.181.165)  14.974 ms  7.875 ms  8.312 ms

 4  te-0-10-0-2-ar01.chartford.ct.hartford.comcast.net (68.85.162.190)  12.326 ms  13.044 ms  12.437 ms

 5  pos-1-5-0-0-ar01.needham.ma.boston.comcast.net (68.85.162.73)  19.212 ms  15.029 ms  14.987 ms

 6  te-4-3-ur01.chelmsfdrdc2.ma.boston.comcast.net (68.87.146.34)  15.249 ms  18.011 ms  30.645 ms

 7  * cdns01.comcast.net (75.75.75.75)  22.459 ms  15.426 ms

[EG]

Thanks. The request for escalation has been made, I am just waiting for a reply. This may not happen until tomorrow.

[UHFhd]

ok ty for you help ! hope it helps other too

[EG]

BTW are you using a router ? If so, try temporarily removing it from the mix and connect the Mac directly to the moden and see if the issue still exists. You'll need to powercycle the modem when you do this and then again when you re-insert it. The router may be acting as a DNS proxy and some have issues doing this.

[UHFhd]

Have used get dns automatically from isp settings and also, use these ip settings entering comcast dns 75.75.75.75 , 75.75.74.74 numbers  manually into wireless router firmware up to date and correct version

Will take router out of mix and retest in AM.

[UHFhd]

wireless taken out of configuration, ethernet port uses different comcast dns numbers so to compare apples to apples manually entered in 75.75.75.75 comcast dns ...... minimum lag time and no timeout using ethernet port connected directly to docsis3 modem

test with wireless back in configuration

   traceroute to 75.75.75.75 (75.75.75.75), 64 hops max, 40 byte packets
 1  removed ip  14.133 ms  8.247 ms  2.502 ms
 2  73.158.64.1 (73.158.64.1)  11.455 ms  11.829 ms  8.005 ms
 3  ge-3-37-ur01.*******.ct.hartford.comcast.net (68.87.181.165)  7.799 ms  12.109 ms  11.014 ms
 4  te-0-10-0-2-ar01.chartford.ct.hartford.comcast.net (68.85.162.190)  16.654 ms  14.751 ms  35.784 ms
 5  pos-1-5-0-0-ar01.needham.ma.boston.comcast.net (68.85.162.73)  16.295 ms  15.104 ms  15.512 ms
 6  te-4-3-ur01.chelmsfdrdc2.ma.boston.comcast.net (68.87.146.34)  21.012 ms  19.897 ms  19.423 ms
 7  * cdns01.comcast.net (75.75.75.75)  18.489 ms  18.688 ms
                    new test wireless router in configuration           no timeout today will try later

[UHFhd]

one last configuration log........ Upstream channnle bonding value Channel ID 2  Frequency 23600000 Hz  Ranging Service ID 6692  Symbol Rate 5.120 Msym/sec  Power Level 39 dBmV  Upstream Modulation [3] QPSK
[3] 64QAM
  Ranging Status Success
 

Downstream Bonding Channel Value Channel ID 8  Frequency 507000000 Hz  Signal to Noise Ratio 37 dB  Downstream Modulation QAM256  Power Level
The Downstream Power Level reading is a snapshot taken at the time this page was requested. Please Reload/Refresh this Page for a new reading
14 dBmV   when using a attenuator knocks that dbmv level down to 11                  

[UHFhd]

timeout again with wireless in mix

traceroute to 75.75.75.75 (75.75.75.75), 64 hops max, 40 byte packets

 1  removed ip  3.175 ms  2.595 ms  2.591 ms

 2  73.158.64.1 (73.158.64.1)  8.979 ms  9.212 ms  10.065 ms

 3  68.87.181.165 (68.87.181.165)  9.137 ms  9.609 ms  7.758 ms

 4  te-0-10-0-2-ar01.chartford.ct.hartford.comcast.net (68.85.162.190)  11.424 ms  13.789 ms  10.531 ms

 5  pos-1-5-0-0-ar01.needham.ma.boston.comcast.net (68.85.162.73)  14.816 ms  14.888 ms  14.877 ms

 6  68.87.146.34 (68.87.146.34)  15.989 ms  15.426 ms  15.727 ms

 7  cdns01.comcast.net (75.75.75.75)  15.548 ms  16.347 ms *

[UHFhd]

Using terminal and snow leopard os command for  clearing out DNS

dscacheutil -flushcache              fixes the problem temporally. When wireless is in the configuration, net monitor see repeated requests to dns just before a timeout . So either its my wireless or the way the dns requests are handled between comcast docsis 3 modem and my wireless .   

[BethKatz]

I'm not good at reading these traces.

I think you confirmed that it works with your Mac connected directly to the modem.

Does the router have the latest firmware? I'm guessing that's not the problem, but it's a good idea to check.

[EG]

We are not analyzing traces here. I only asked the poster to supply one to their default DNS server so that a CC employee like jlivingood or ctg1701a could see which DNS server they were being directed to as this originally appeared to be a DNS issue. I've seen this issue before with their new DNSsec servers and these guys ask for a trace to them..

[UHFhd]

Earlier in post had mentioned newest firmware and correct version ,but thanks for input. Thanks for the help EG. Am going to use the old comcast dns #'s, that hard wireing to ethernet port uses see if that makes a difference .

[UHFhd]

Entering manually older comcast dns #s 68.87.71.230,68,87,73,246 along with a change to firefox proxy settings from User system proxy settings to No proxy has made a difference to speed of loading pages both in text page and pics in craigslist . 

[EG]

Be advised that I understand that in the near future everyone will be being switched to the DNSSec servers by default and that those old hard coded IP's may no longer be valid.

[UHFhd]

On further testing last post did not fix timeout . The only thing that seems to help is clearing out cache in browser and using terminal command after each restart of computer and before visit to craigslist.

[UHFhd]

 this seems to have worked , ...... so far 

DNS Prefetching

Firefox attempts to speed up loading new websites by using DNS Prefetching, which can cause page load errors with some system configurations. To disable DNS Prefetching:

1. In the Location bar, type about:config and press Return.

   • The about:config "This might void your warranty!" warning page may appear. ClickI'll be careful, I promise!, to continue to the about:config page.
2. Hold down the Ctrl key while you click in the list of preferences, select New, and then select Boolean.
3. In the Enter the preference name window, enter network.dns.disablePrefetch and click OK.
4. Select true when prompted to set the value and click OK.

[UHFhd]

http://www.macworld.com/article/154149/2010/09/dns_prefetching.html

[BethKatz]

Thank you for the link.

[UHFhd]

your welcome

[ComcastChrisGr]

---

UHFhd wrote:

timeout again with wireless in mix

traceroute to 75.75.75.75 (75.75.75.75), 64 hops max, 40 byte packets

 1  removed ip  3.175 ms  2.595 ms  2.591 ms

 2  73.158.64.1 (73.158.64.1)  8.979 ms  9.212 ms  10.065 ms

 3  68.87.181.165 (68.87.181.165)  9.137 ms  9.609 ms  7.758 ms

 4  te-0-10-0-2-ar01.chartford.ct.hartford.comcast.net (68.85.162.190)  11.424 ms  13.789 ms  10.531 ms

 5  pos-1-5-0-0-ar01.needham.ma.boston.comcast.net (68.85.162.73)  14.816 ms  14.888 ms  14.877 ms

 6  68.87.146.34 (68.87.146.34)  15.989 ms  15.426 ms  15.727 ms

 7  cdns01.comcast.net (75.75.75.75)  15.548 ms  16.347 ms *

---

I have verified all caches in the Boston region that respond to our Anycast nodes and they all return the correct response for:  newlondon.craigslist.org

I also ran the same requests against http://dns.comcast.net/dig-tool.php and they are all resolving as well.

You may see some timeouts sending pings and traceroutes to the Anycast nodes since we rate limite ICMP. 

If you are still having issues, please run a few dig or nslookup commands directly at the 75.75.75,75 Anycast and please post those.

Thanks

Chris

Comcast

[EG]

Thanks for peeking in here Chris.

[UHFhd · Accepted solution]

This seems to have been a Firefox , Safari issue setup running with older wireless router . Since making those changes to firefox and safari i have had NO issues.

DNS Prefetching

Firefox attempts to speed up loading new websites by using DNS Prefetching, which can cause page load errors with some system configurations. To disable DNS Prefetching:

• In the Location bar, type about:config and press Return.
  • The about:config "This might void your warranty!" warning page may appear. ClickI'll be careful, I promise!, to continue to the about:config page.
• Hold down the Ctrl key while you click in the list of preferences, select New, and then select Boolean.
• In the Enter the preference name window, enter network.dns.disablePrefetch and click OK.
• Select true when prompted to set the value and click OK.
•                                  
• Safari Link              Snow Leopard, Motorola docsis 3, and Netgear WGT624

[EG]

N.M....