Bug 23862 - Dns.GetHostAddresses("localhost") !=
Summary: Dns.GetHostAddresses("localhost") !=
Status: NEW
Alias: None
Product: Class Libraries
Classification: Mono
Component: System ()
Version: 3.2.x
Hardware: PC Linux
: --- normal
Target Milestone: Untriaged
Assignee: Bugzilla
Depends on:
Reported: 2014-10-15 17:05 UTC by Peter Hultqvist
Modified: 2014-10-15 17:11 UTC (History)
1 user (show)

Is this bug a regression?: ---
Last known good build:

Notice (2018-05-24): bugzilla.xamarin.com is now in read-only mode.

Please join us on Visual Studio Developer Community and in the Xamarin and Mono organizations on GitHub to continue tracking issues. Bugzilla will remain available for reference in read-only mode. We will continue to work on open Bugzilla bugs, copy them to the new locations as needed for follow-up, and add the new items under Related Links.

Our sincere thanks to everyone who has contributed on this bug tracker over the years. Thanks also for your understanding as we make these adjustments and improvements for the future.

Please create a new report for Bug 23862 on GitHub or Developer Community if you have new information to add and do not yet see a matching new report.

If the latest results still closely match this report, you can use the original description:

  • Export the original title and description: GitHub Markdown or Developer Community HTML
  • Copy the title and description into the new report. Adjust them to be up-to-date if needed.
  • Add your new information.

In special cases on GitHub you might also want the comments: GitHub Markdown with public comments

Related Links:

Description Peter Hultqvist 2014-10-15 17:05:09 UTC
This issue appears when the server hostname is set to "localhost".
This happened to be the default on some vps hosting services.

1. Run: hostnamectl set-hostname localhost

2. Run some tests

2a.# ping localhost
   64 bytes from localhost ( icmp_seq=1 ttl=64 time=0.041 ms

2b.# host localhost
   localhost has address
   localhost has IPv6 address ::1
3. Run the following

    var ip = System.Net.Dns.GetHostAddresses("localhost")

Expected result:

ip = []

Actual result:

ip = [100....., 192.168....., 172......]

These are all 3 the IP addresses of the network interfaces.
Note that is not there.