Closed Bug 239357 Opened 20 years ago Closed 20 years ago

Reverse DNS lookups are degrading performance

Categories

(Core :: Networking, defect)

Product:
Core
Component:
Networking
Platform:
x86
Linux
Type:
defect
Priority:
Not set
Severity:
major

Tracking

()

Status:
RESOLVED DUPLICATE of bug 239358

People

(Reporter: bugzilla, Assigned: darin.moz)

References

(
URL
)

Details

User-Agent:       Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.6) Gecko/20040114
Build Identifier: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.6) Gecko/20040114

Here's a tcpdump run and some comments to demonstrate the problem

scampbell:~ # tcpdump -n -i eth0 port 53
tcpdump: listening on eth0
09:58:11.094628 10.8.178.10.32785 > 10.8.171.87.53:  47349+ AAAA? www.google.com
. (32) (DF)
09:58:11.119236 10.8.171.87.53 > 10.8.178.10.32785:  47349 1/0/0 CNAME[|domain] (DF)
09:58:11.119537 10.8.178.10.32785 > 10.8.171.87.53:  47350+ A? www.google.com. (
32) (DF)
09:58:11.121283 10.8.171.87.53 > 10.8.178.10.32785:  47350 3/1/0 CNAME[|domain] (DF)
09:58:11.121571 10.8.178.10.32785 > 10.8.171.87.53:  47351+ PTR? 104.167.233.64.
in-addr.arpa. (45) (DF)
        four seconds elapse while we lookup the reverse dns for the google site
        This seems unnecessary and disfunctional
09:58:16.121846 10.8.178.10.32785 > 10.8.171.87.53:  47351+ PTR? 104.167.233.64.
in-addr.arpa. (45) (DF)
09:58:21.123186 10.8.178.10.32785 > 10.8.171.87.53:  47352+ AAAA? www.google.com
. (32) (DF)
09:58:21.147515 10.8.171.87.53 > 10.8.178.10.32785:  47352 1/0/0 CNAME[|domain] (DF)
09:58:21.148001 10.8.178.10.32785 > 10.8.171.87.53:  47353+ PTR? 99.167.233.64.i
n-addr.arpa. (44) (DF)
        We seem to try again for another 5 seconds lost
09:58:26.148848 10.8.178.10.32785 > 10.8.171.87.53:  47353+ PTR? 99.167.233.64.i
n-addr.arpa. (44) (DF)
09:58:31.150124 10.8.178.10.32785 > 10.8.171.87.53:  47354+ AAAA? www.google.com
. (32) (DF)
09:58:31.175291 10.8.171.87.53 > 10.8.178.10.32785:  47354 1/0/0 CNAME[|domain] (DF)
09:58:39.130214 10.8.171.87.53 > 10.8.178.10.32785:  47351 ServFail 0/0/0 (45) (DF)
09:58:39.130239 10.8.171.87.53 > 10.8.178.10.32785:  47351 ServFail 0/0/0 (45) (DF)
09:58:49.131367 10.8.171.87.53 > 10.8.178.10.32785:  47353 ServFail 0/0/0 (44) (DF)
09:58:49.131405 10.8.171.87.53 > 10.8.178.10.32785:  47353 ServFail 0/0/0 (44) (DF)
        Ultimately it took us 38 seconds to open the web page, almost all time
was waiting
        on reverse lookup records that do not seem to serve a usefull purpose.


Reproducible: Always
Steps to Reproduce:
1.Start with a clean DNS cache and new copy of mozilla
2 Go to the google site
3.Watch as things are slow to occur initially, tcpdump is great help

Actual Results:  
It took 38 seconds to open the page.  See the attached and annoted tcpdump report

Expected Results:  
Opened the page immediately, I suspect there is no good reason to do the reverse
lookups that appear to be causing the problem.

I've put this to 'Major' as it will likely cause many bad perceptions about the
excellent Mozilla software.
Assignee: general → darin
Component: Browser-General → Networking
QA Contact: general → benc

*** This bug has been marked as a duplicate of 239258 ***
Status: UNCONFIRMED → RESOLVED
Closed: 20 years ago
Resolution: --- → DUPLICATE
sorry for bugspam
Status: RESOLVED → UNCONFIRMED
Resolution: DUPLICATE → ---

*** This bug has been marked as a duplicate of 239358 ***
Status: UNCONFIRMED → RESOLVED
Closed: 20 years ago → 20 years ago
Resolution: --- → DUPLICATE
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