Bug 991550

Summary:	curl resolves DNS names to IPv6 addresses on an IPv4-only host
Product:	[Fedora] Fedora	Reporter:	James <james>
Component:	curl	Assignee:	Kamil Dudka <kdudka>
Status:	CLOSED INSUFFICIENT_DATA	QA Contact:	Fedora Extras Quality Assurance <extras-qa>
Severity:	high	Docs Contact:
Priority:	unspecified
Version:	19	CC:	james, kdudka, paul
Target Milestone:	---
Target Release:	---
Hardware:	x86_64
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	Bug Fix
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2013-09-17 16:08:58 UTC	Type:	Bug
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:

Description James 2013-08-02 17:36:52 UTC

Curl attempts to contact IPv6 addresses when the host does not have an interface with an IPv6 address. This seems to happen 9/10 times on this machine. Programs such as firefox, ping, nslookup and ssh work correctly. This causes yum to fail to update, since yum uses curl.

Version:
========

[james@mufasa ~]$ curl -V
curl 7.29.0 (x86_64-redhat-linux-gnu) libcurl/7.29.0 NSS/3.14.3.0 zlib/1.2.7 libidn/1.26 libssh2/1.4.3
Protocols: dict file ftp ftps gopher http https imap imaps ldap ldaps pop3 pop3s rtsp scp sftp smtp smtps telnet tftp 
Features: AsynchDNS GSS-Negotiate IDN IPv6 Largefile NTLM NTLM_WB SSL libz


How reproducible:
=================

This occurs 9/10 times on this machine.

Steps to Reproduce:
===================

1. Installed Fedora 19 from the full DVD.
2. Set IPv6 in NetworkManager -> IPv6 Settings -> Ignore.
3. Disable IPv6 using:

$sudo sysctl -w net.ipv6.conf.all.disable_ipv6=1

4. $curl fedoraproject.org

Actual results:
===============

curl: (6) Could not resolve host: fedoraproject.org; Name or service not known

Expected results:
=================

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
<html>
...

Additional info:
================

Forcing curl to use IPv4 causes it to work correctly every time:

$ curl -4 fedoraproject.org
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
<html>
...

Comment 1 Kamil Dudka 2013-08-09 09:59:05 UTC

Please attach the output of the following command:

$ getent ahosts fedoraproject.org

Comment 2 Kamil Dudka 2013-09-17 16:08:58 UTC

More than a month in needinfo, closing out...