CODEWITHSUNDEEP
linuxcurlterminalfedora
Nayana Adassuriya
Nayana Adassuriya

Reputation: 24756

curl: (6) Could not resolve host: google.com; Name or service not known

when I try to load a web page to terminal it gives curl: (6) Could not resolve host error.

I have internet in my PC and trying from my home internet connection. So as I there is no any proxy involve here. 

[root@localhost kevin]# curl http://google.com
curl: (6) Could not resolve host: google.com; Name or service not known

clean all and tried again but no lucky.

But if I use IP instead of the domain name, it works fine.

[root@localhost kevin]# curl http://173.194.46.0

any clue please?

Upvotes: 97

Views: 714484

Answers (10)

Virgar Poulsen
Virgar Poulsen

Reputation: 477

Could be a firewall issue.

Try:

ufw allow out 53
reboot

Upvotes: 2

ilgnv88
ilgnv88

Reputation: 21

In my case, the problem was in the Static Route Table. Must be removed if a static route was previously added

Upvotes: 0

AJB
AJB

Reputation: 7590

My case on MacOS was simple: I closed the iTerm window I was using and opened a new one.

It seems likely that this is an issue with CURL cacheing DNS responses given that I was messing around with my DNS when I ran into the same error as the OP.

Upvotes: 0

jez001
jez001

Reputation: 31

I had an issue with IPV6 that suddenly showed up in wordpress admin where curl failed to connect to wordpress.org etc giving

An unexpected error occurred. Something may be wrong with WordPress.org

and also

Installation failed: Download failed. cURL error 28: Resolving timed out after 10005 milliseconds

I eventually sorted by adding the following as a php file in mu-plugins:

add_action( 'http_api_curl', function( $curl_handle ) { curl_setopt( $curl_handle, CURLOPT_IPRESOLVE, CURL_IPRESOLVE_V4 );});

and also when using curl directly in php by using the following option in the options array:

curl_setopt_array($curl, array(CURLOPT_IPRESOLVE => CURL_IPRESOLVE_V4));

The OS is IBM i (OS400/i5OS) v7.2 running on Power 6 and the php version is 8.1.10. Interestingly IPV6 is not active on the box.

Upvotes: 0

nikhil2000
nikhil2000

Reputation: 188

In Our case, the command was passed through mail/skype and the person who needs to execute copied an extra space.

we found that extra space after an hour and removing that made it work.

Upvotes: 1

Houman
Houman

Reputation: 66380

There is no need to disable IPv6 as the answer suggests. The reason curl fails is simply because the DNS resolution is missing.

There is one liner solution to this.

If you care about what is inside /etc/resolv.conf then append it:

echo 'nameserver 1.1.1.1' | sudo tee -a /etc/resolv.conf >/dev/null

I usually don't care and just replace the content of the file:

echo 'nameserver 1.1.1.1' | sudo tee /etc/resolv.conf >/dev/null

Upvotes: 15

Chris Suszyński
Chris Suszyński

Reputation: 1554

I have today similar problem. But weirder.

  • host - works host pl.archive.ubuntu.com
  • dig - works on default and on all other DNS's dig pl.archive.ubuntu.com, dig @127.0.1.1 pl.archive.ubuntu.com
  • curl - doesn't work! but for some addresses it does. WEIRD! Same in Ruby, APT and many more.
$ curl -v http://google.com/
*   Trying 172.217.18.78...
* Connected to google.com (172.217.18.78) port 80 (#0)
> GET / HTTP/1.1
> Host: google.com
> User-Agent: curl/7.47.0
> Accept: */*
>
< HTTP/1.1 302 Found
< Cache-Control: private
< Content-Type: text/html; charset=UTF-8
< Referrer-Policy: no-referrer
< Location: http://www.google.pl/?gfe_rd=cr&ei=pt9UWfqXL4uBX_W5n8gB
< Content-Length: 256
< Date: Thu, 29 Jun 2017 11:08:22 GMT
<
<HTML><HEAD><meta http-equiv="content-type" content="text/html;charset=utf-8">
<TITLE>302 Moved</TITLE></HEAD><BODY>
<H1>302 Moved</H1>
The document has moved
<A HREF="http://www.google.pl/?gfe_rd=cr&ei=pt9UWfqXL4uBX_W5n8gB">here</A>.
</BODY></HTML>
* Connection #0 to host google.com left intact

$ curl -v http://pl.archive.ubuntu.com/
* Could not resolve host: pl.archive.ubuntu.com
* Closing connection 0
curl: (6) Could not resolve host: pl.archive.ubuntu.com

Revelation

Eventually I used strace on curl and found that it was connection to nscd deamon.

connect(4, {sa_family=AF_LOCAL, sun_path="/var/run/nscd/socket"}, 110) = 0

Solution

I've restarted the nscd service (Name Service Cache Daemon) and it helped to solve this issue!

systemctl restart nscd.service

Upvotes: 7

Nayana Adassuriya
Nayana Adassuriya

Reputation: 24756

Issues were:

  1. IPV6 enabled
  2. Wrong DNS server

Here is how I fixed it:

IPV6 Disabling

  • Open Terminal
  • Type su and enter to log in as the super user
  • Enter the root password
  • Type cd /etc/modprobe.d/ to change directory to /etc/modprobe.d/
  • Type vi disableipv6.conf to create a new file there
  • Press Esc + i to insert data to file
  • Type install ipv6 /bin/true on the file to avoid loading IPV6 related modules
  • Type Esc + : and then wq for save and exit
  • Type reboot to restart fedora
  • After reboot open terminal and type lsmod | grep ipv6
  • If no result, it means you properly disabled IPV6

Add Google DNS server

  • Open Terminal
  • Type su and enter to log in as the super user
  • Enter the root password
  • Type cat /etc/resolv.conf to check what DNS server your Fedora using. Mostly this will be your Modem IP address.
  • Now we have to Find a powerful DNS server. Luckily there is a open DNS server maintain by Google.
  • Go to this page and find out what are the "Google Public DNS IP addresses"
  • Today those are 8.8.8.8 and 8.8.4.4. But in future those may change.
  • Type vi /etc/resolv.conf to edit the resolv.conf file
  • Press Esc + i for insert data to file
  • Comment all the things in the file by inserting # at the begin of the each line. Do not delete anything because can be useful in future.

  • Type below two lines in the file

    nameserver 8.8.8.8
    nameserver 8.8.4.4

    -Type Esc + : and then wq for save and exit

  • Now you are done and everything works fine (Not necessary to restart).
  • But every time when you restart the computer your /etc/resolv.conf will be replaced by default. So I'll let you find a way to avoid that.

Here is my blog post about this: http://codeketchup.blogspot.sg/2014/07/how-to-fix-curl-6-could-not-resolve.html

Upvotes: 112

Benjamin B
Benjamin B

Reputation: 41

Try nslookup google.com to determine if there's a DNS issue. 192.168.1.254 is your local network address and it looks like your system is using it as a DNS server. Is this your gateway/modem router as well? What happens when you try ping google.com. Can you browse to it on a Internet web browser?

Upvotes: 2

Sathish
Sathish

Reputation: 3870

Perhaps you have some very weird and restrictive SELinux rules in place?

If not, try strace -o /tmp/wtf -fF curl -v google.com and try to spot from /tmp/wtf output file what's going on.

Upvotes: 7

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