DNS failing in wget/yum/curl, works in ping, nslookup

awbacker · #1 8th June 2011, 08:24 PM

I am having a problem with DNS resolving in wget (and firefox, yum), but working in ping and nslookup. I have seen this reported elsewhere with FC10/11, but nothing on 15.

Interestingly, when using wget to fetch 'google.com' it gets some sort of an answer, including an IPv6 address, and then tries to fetch from the v6 one (and hangs there.)

UPDATE: using 'wget -4 [url]' works fine. This appears to be something about IPv6, but as far as I can tell it is disabled. In network manager for the wired connection it says 'ignore' for v6.

I have followed all the suggestions on the various forums (including here), all to no avail.

Fedora 15 - clean install - Running inside Parallels (latest)
name is 'fedora15.smackbook', not 'fedora15.localdomain'
mdns installed (nss-mdns-0.10-9.fc15.i686)
wget/curl/firefox fail to resolve
wget works with IP address, same with curl
ping/traceroute work
yum fails to resolve repo mirrors, but fallsback to 'fedora' which somehow works (but super slow)

Things I have tried:

getent hosts mirrors.issp.co.th -- resolves fine
editing /etc/nsswitch.conf file
editing the connection (in gnome) to use the actual nameservers directly

My resolve.conf file:

Code:

domain localdomain
search localdomain smackbook  #name of the macbook
nameserver 10.211.55.1           #ip assigned by parallels

My nsswitch.conf 'host' line. All the others just say 'file'

Code:

hosts: files mds4_minimal dns
# have also changed to 'files dns', no success
# remove the [NOTFOUND = return] from after mds4_minimal

/etc/hosts file:

Code:

127.0.0.1 localhost.localdomain localhost
::1 localhost6.localdomain6 localhost6

I am stumped. I have run through a few other things mentioned here and there, but they are all older and haven't resolved it. Here are a few of the bugs and posts:

https://bugzilla.redhat.com/show_bug.cgi?id=504951
http://serverfault.com/questions/764...t-resolve-host

(new posts are checked for words and how many urls they contain, so I can only include two. very strange.)

Thanks for any help,

Andrew

---------- Post added at 07:24 PM ---------- Previous post was at 04:33 PM ----------

Tried blacklisting IPv6, and nothing changed.

Added /etc/modprobe.d/blacklist-ipv6.conf

Code:

install ipv6 /bin/true
blacklist ipv6

Turned off 'ip6tables' via 'chkconfig ip6tables off'

Now the ipv6 module isn't loaded according to 'lsmod'. Still wget fails unless I force it to use v4 via 'wget -4 [url].

stoat · #2 9th June 2011, 02:11 AM

Quote:

Originally Posted by awbacker

Code:

nameserver 10.211.55.1           #ip assigned by parallels

Nevertheless, I still would try entering some DNS nameserver IP addresses such as your ISP's or OpenDNS's. You easily can test the idea by manually editing /etc/resolv.conf, but your changes there will not survive a reboot. If the idea works, then enter the IP addresses into NetworkManager. I have to do that for wget, too.

To enter DNS nameserver IP addresses for NetworkManager, start the NetworkManager connection editor (nm-connection-editor). Find the connection, "Edit", "IPv4 Settings" tab, change "Method" to "Automatic (DHCP) addresses only", enter the DNS nameserver IP addresses in the text box separated by a comma, "Apply", "Close". NetworkManager will write them into /etc/resolv.conf. If you're using something other than NetworkManager to control the interface, the same thing applies (IMO). I just won't know the steps precisely.

Anyway, it won't hurt to try.

awbacker · #3 9th June 2011, 08:30 AM

I tried those changes to no effect. Dang.

I should note that blacklisting IPV6 let Firefox start working, and today wget seems a bit more likely to properly resolve, but it will fall back to it's old ways. I'm using FF to go the same hosts sometimes, so I think that is just due to DNS caching.

Also, all attempts to connect via FTP fail (through curl/wget) with 425 connection not opened. Work fine in FF though.

WGET -4 FTP:// work fine
WGET -4 HTTP:// works fine

It looks like WGET is still trying to use ipv6 sometimes. Also, curl will function with FTP, but one in 10 tries, maybe.

All of this is because I need a fast fedora mirror. The one in thailand works great, IF i stick to FTP. That gives me 500KB/s downloads, but the HTTP downloads max out at 50KB/s. Not sure if that is the server, or something to do with a squid proxy that sits in between. I have no control over that, though.

~ Andrew

***glennzo*** · #4 9th June 2011, 09:17 AM

Your reslove.conf vs mine.
Yours:

Code:

domain localdomain
search localdomain smackbook  #name of the macbook
nameserver 10.211.55.1           #ip assigned by parallels

Mine (generated by the system - not altered by me)

Code:

# Generated by NetworkManager
domain hsd1.ma.comcast.net.
search hsd1.ma.comcast.net.
nameserver 68.87.71.230
nameserver 68.87.73.246

Perhaps yours is lacking a line or 2? Why is the nameserver a 10. number? Isn't that a bit odd. I thought 10.xxx was reserved for lan.

awbacker · #5 9th June 2011, 01:44 PM

It is reserved. This is running inside parallels, so that is the IP of the parallels server/hypervisor/overprotective big brother/etc.

I just ran all the updates suggested by yum, which took forever (at, 30Kb/s this time), but at least gnome 3 isn't in fallback mode now. I wish it was! Still the same issues though, but FF still works, and wget -4 still works, but wget fails.

Also...

I have examples I want to post. But.. I'm sick of spending so much time trying to remove or suitably mangle all the URLS so that the post will go up, and so I've given up.

Is there some way to get that fixed on this board? I could see it some places, but a site dedicated to support for linux/programming/networking/etc really falls down when you can't post even url's to the bugs you have researched, or include examples because they run afoul of some silly limit. Just don't turn them into URLs automatically, or add rel="nofollow". Arg.

stoat · #6 9th June 2011, 05:41 PM

Quote:

Originally Posted by awbacker

I have examples I want to post. But.. I'm sick of spending so much time trying to remove or suitably mangle all the URLS so that the post will go up, and so I've given up.

Is there some way to get that fixed on this board? I could see it some places, but a site dedicated to support for linux/programming/networking/etc really falls down when you can't post even url's to the bugs you have researched, or include examples because they run afoul of some silly limit. Just don't turn them into URLs automatically, or add rel="nofollow". Arg.

It's not broken. It's intentional. Those posts you mentioned probably are being sent to the moderation queue automatically. Someday, soon, eventually, it will stop happening to you. Without it, especially at certain hours of the day, it doesn't take very long for all legitimate threads to be pushed off the first page of New Posts by phony threads that are actually pushing links to sunglasses, tennis shoes, handbags, and porn.

So for now, go ahead and create the post or thread. If the URLs or images or whatever prevent you from seeing it, then send a private message to a staff member. Or wait a while for the modertion queue to be reviewed by somebody.

P.S.: I just checked the moderation queue and it was empty.