Bug 401850 - excessive DNS usage DOS's router
Summary: excessive DNS usage DOS's router
Status: REPORTED
Alias: None
Product: akregator
Classification: Applications
Component: general (show other bugs)
Version: 5.8.3
Platform: Kubuntu Linux
: NOR major
Target Milestone: ---
Assignee: kdepim bugs
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2018-12-07 05:45 UTC by kdebugs
Modified: 2023-02-03 07:50 UTC (History)
1 user (show)

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Description kdebugs 2018-12-07 05:45:10 UTC
I have recently experienced intermittent network dropouts. I believe I traced the issue to Akregator making a large number of DNS queries, but I'm not qualified to assess that.

I run dd-wrt on an ancient Linksys router. The status page for the router shows ~80 open connections with Firefox running. I start Akregator and the refreshing of the feeds causes this number to reach 1024 connections in a few seconds (sometimes I need to do a manual refresh of the feeds to reach this many.) Inspection of the connections list on the router shows numerous TIME_WAIT sockets to google IPs (Example IPs: 172.217.3.211 and 216.58.195.83). I use google nameservers (75.75.75.75) so I conjectured that Akregator is making numerous DNS calls. 1024 is the "IP Filter Maximum Ports" value for the router, so the router is rendered unusable until the TIME_WAITs time out.

I'm sure a more modern or differently-configured router could handle this better, but given that I've used the same feeds and same router for years with Akregator, it seems like something has changed recently. Also, I have only 103 feeds (~620 unread articles), and it seems odd to use >1000 DNS calls to refresh those feeds (and pull no new articles in.)

I thus wondered if there is some accidental over-usage of DNS going on, but I will stop speculating. I don't know if the finger points to Akregator or some underlying OS issue.

I recently upgraded from 18.04 to 18.10, and the net issues seem to have started after that, but to be honest I upgraded several weeks ago and only noticed the net issues in the last week, so I can't be sure of the association.

KDE Plasma Version: 5.13.5
KDE Frameworks Version: 5.50.0
Qt Version: 5.11.1
Linux <hostname> 4.18.0-12-generic #13-Ubuntu SMP Wed Nov 14 15:17:05 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux
Comment 1 Justin Zobel 2023-01-19 00:18:52 UTC
Thank you for reporting this issue in KDE software. As it has been a while since this issue was reported, can we please ask you to see if you can reproduce the issue with a recent software version?

If you can reproduce the issue, please change the status to "REPORTED" when replying. Thank you!
Comment 2 kdebugs 2023-01-19 00:39:43 UTC
I no longer have a router with dd-wrt so I don't have an easy way to check, but netstat on my local machine doesn't show excessive sockets being opened. Perhaps the issue is gone?
Comment 3 Bug Janitor Service 2023-02-03 05:01:51 UTC
Dear Bug Submitter,

This bug has been in NEEDSINFO status with no change for at least
15 days. Please provide the requested information as soon as
possible and set the bug status as REPORTED. Due to regular bug
tracker maintenance, if the bug is still in NEEDSINFO status with
no change in 30 days the bug will be closed as RESOLVED > WORKSFORME
due to lack of needed information.

For more information about our bug triaging procedures please read the
wiki located here:
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If you have already provided the requested information, please
mark the bug as REPORTED so that the KDE team knows that the bug is
ready to be confirmed.

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