• Status: Solved
  • Priority: Medium
  • Security: Public
  • Views: 708
  • Last Modified:

Delay following DNS response:

I've been using Ethereal to help narrow this annoying problem down.  Here's what I have.

I have been annoyed that my home page (google) takes longer to load than I wouild expect.  I realized it was actually an issue when my girlfriend's machine was consistently NOT having this problem, whereas mine WAS.  Well it turns out that the packet capture shows a DNS query to the router, immediately followed by a response with the resolved name.  However, then there is abouit a 7 second delay before the next packet goes out.

In order to eliminate the browser as being the issue, I repeated this test using PING.  Here are the results (pretty much the same as when bringing up the main google web page):

No.     Time        Source                Destination           Protocol Info
      8 0.730549    192.168.0.103         192.168.0.1           DNS      Standard query A WWW.GOOGLE.COM
      9 0.743367    192.168.0.1           192.168.0.103         DNS      Standard query response CNAME www.l.GOOGLE.COM A 216.239.37.104 A 216.239.37.99
     22 7.757377    192.168.0.103         216.239.37.104        ICMP     Echo (ping) request
     23 7.770849    216.239.37.104        192.168.0.103         ICMP     Echo (ping) reply
     24 8.770850    192.168.0.103         216.239.37.104        ICMP     Echo (ping) request
     25 8.798386    216.239.37.104        192.168.0.103         ICMP     Echo (ping) reply
     26 9.770852    192.168.0.103         216.239.37.104        ICMP     Echo (ping) request
     27 9.796171    216.239.37.104        192.168.0.103         ICMP     Echo (ping) reply


Aside from me, the printer, and the Tivo, the network is pretty quiet.  The above capture is filtered, but as you can see from the first column (packet number), what I pasted here is a third of the total packets.  

I am using DHCP both for IP and DNS, so since the other machine is not having this lag issue, I suspect it is with my own.

I don't suspect any wireless radio issues, since in such a case I would expect sluggishness all the time together with packet errors.  I do have an "excellent" wifi signal power reading, as far as that goes.

Earlier in the day, I thought I traced the problem to some "support.com" software which was still hanging aroiund from Adelphia cable (since I saw their server being used almost like a proxy in the packet capture).  I have removed the software, there are no more requests to their server, but I still have this time lag.

Thanks in advance to anyone who can help fix this annoying issue.
0
mrdtn
Asked:
mrdtn
  • 2
1 Solution
 
ISoulCommented:
I know you say they are both running DHCP for IP and DNS, but have you confirmed that the two machines are in fact using the same DNS server?
0
 
mrdtnAuthor Commented:
Yes.  They are both using the router 192.168.0.1 as the DNS, which in turn is using some Verizon FIOS DNS at 78.??.??.??.  I did a packet capture using the other machine.  I would run it again and post it right now, but it is currently being used.

0
 
mrdtnAuthor Commented:
Okay,

I guess I'm going to answer my own question.  I am going to request that it be closed but not deleted, since the information here will still benefit the community.

After further troubleshooting, the thing that fixed this problem was disabling Internet Connection Sharing (ICS).  I'm not even sure why it was enabled.  I may have left it enabled when I was using ICS to allow a Wifi enabled PDA connect to the net via an ad-hoc connection to my laptop.  I thought I had disabled it when I was done using it for that purpose, but I guess not.  I disabled it and no more delay.  Problem fixed.

If any other networking expert can provide more of an explanation as to what may have been going on here, it would be helpful.  I fix a lot of problems, but I hate it when I don't know all the reasons why a particular solution fixed a particular problem.  All I can ascertain is that ICS is doing a lot of pre-emptive timed waits or something.

--

mrdtn
0
 
GranModCommented:
Closed, 250 points refunded.
GranMod
The Experts Exchange
Community Support Moderator of all Ages
0

Featured Post

Get quick recovery of individual SharePoint items

Free tool – Veeam Explorer for Microsoft SharePoint, enables fast, easy restores of SharePoint sites, documents, libraries and lists — all with no agents to manage and no additional licenses to buy.

  • 2
Tackle projects and never again get stuck behind a technical roadblock.
Join Now