Bug 211767

Summary:	Strange DNS behaviour: Konqueror repeatedly resolves all domain names it sees.
Product:	[Applications] konqueror	Reporter:	Staffan Palmroos <spalmroos>
Component:	khtml	Assignee:	Konqueror Developers <konq-bugs>
Status:	RESOLVED NOT A BUG
Severity:	normal	CC:	andrew.crouthamel, aspotashev, tiposchi
Priority:	NOR
Version First Reported In:	unspecified
Target Milestone:	---
Platform:	Gentoo Packages
OS:	Linux
Latest Commit:		Version Fixed In:
Sentry Crash Report:

Description Staffan Palmroos 2009-10-25 12:44:37 UTC

Version:            (using KDE 4.3.2)
Compiler:          gcc 4.3.2 
OS:                Linux
Installed from:    Gentoo Packages

For a while now, I've noticed (using Wireshark) that my computer repeatedly was making a lot of DNS request, even for addresses I've never seen before. I was afraid I'd contracted a virus or trojan or something. It turns out, the problem is with Konqueror.

It seems Konqueror is periodically resolving all domain names it sees, even if it's never been used in any way. To test:

1. Create a simple web page containing a link to some made up domain:
<html><head></head>
<body><a href="http://www.somemadeupdomain.com">link</a>
</body></html>

2. Fire up Wireshark, use 'dns.qry.name == "www.somemadeupdomain.com"'  as filter.

3. Open the page created in (1) in Konqueror. There is no need to click on "link", just show the page.

4. In the Wireshark window, you will now see DNS requests for www.somemadeupdomain.com every 400 seconds.

I think this behaviour is really bad. I normally have many browser windows open at the time, with pages often containing a lot of links (google results, advertising, news articles and what not). This makes Konqueror do thousands of DNS requests over and over. It even went so far that Google once complained that something was making automated queries from my computer.

To fix:
Change Konqueror to only do DNS request when they are actually needed.

Comment 1 Staffan Palmroos 2009-10-25 13:27:33 UTC

In fact, there is no need to create the page mentioned in the last post. Just viewing this report in Konqueror makes it start to resolve www.somemadeupdomain.com over and over.

Comment 2 Salvo "LtWorf" Tomaselli 2009-11-14 18:53:06 UTC

Yes and no. Creating that page i can't see any weird dns request.
But yes, konqueror does DNS caching (just like chrome and other browsers). It is done so when you click on a link, it won't waste time with the DNS request.
I think this feature should be configurable rather than a built-in behavior, but rather than a bug, i see that like a feature request of making it configurable.

Comment 3 Tommi Tervo 2009-11-14 19:42:44 UTC

It's configurable, we just don't have GUI (yet)

You can add following values to konquerorrc:
DNSPrefetch=Enabled, Disabled, OnlyWWWAndSLD

Comment 4 Andrew Crouthamel 2018-11-06 15:12:33 UTC

Dear Bug Submitter,

This bug has been stagnant for a long time. Could you help us out and re-test if the bug is valid in the latest version? I am setting the status to NEEDSINFO pending your response, please change the Status back to REPORTED when you respond.

Thank you for helping us make KDE software even better for everyone!

Comment 5 Alexander Potashev 2018-11-06 23:28:43 UTC

Status as of konqueror-18.04.3 on Fedora 28; KF 5.48.0; Qt 5.11.1:

When Konqueror engine is set to "KHTML", this is still reproducible (unless you edit the config file by hand).

When Konqueror engine is set to "WebEngine", this is not reproducible. This sounds reasonable as it's hard to integrate DNS prefetch into QWebEngine.

Comment 6 Andrew Crouthamel 2018-11-07 08:37:33 UTC

Thanks for the update!

Comment 7 Alexander Potashev 2018-11-07 11:29:51 UTC

I would say it is not fixed as 99% of users will be unable to use the DNSPrefetch setting due to its obscurity.