Slow DNS Resolution and the 2.6 kernel.

[hard candy]

After I had upgraded to the 2.6 kernel series, my internet connections had slowed down. I have tried various remedies over the past few months with just incremental upgrades in speed in resolving internet speed. It always seemed to boil down to DNS resolution.
Well, I finally found out what was wrong. When I upgraded the kernel I had enabled IPV6 in the networking options. At the time I always figured, what can it hurt? Well, the post i read pointed out that the newer kernels try to use IPV6 to connect first to servers. And since most of the nameservers still use IPV4 protocol, the first attempt with IPV6 had to time out and then the IPV4 protocol would take over.
So I recompiled a new kernel with IPV6 turned off and I am back to the old fast speeds. Yeah!
So if anyone is having a similiar problem with DNS resolution, try the 2.6 kernel without IPV6 enabled and see if there is a difference.

[thedangerouscre]

:D I cam to the same conclusion as you

i just compiled my 2.6.6 kernel and my net card would hang on initialization until i removed ipv6 from my kernel. My internet is
running smooth too

[MMYoung]

GREAT TIP!!!!
I've been having a LOT of problems with just this very thing since I've upgraded to 2.6.6. Especially the "doubleclick" ads on this website. Sometimes it would take forever for them to load, if at all. Sometimes my connection would "hang" and I couldn't use the 'Net at all. Would open a terminal and type in ping www.whatever.com and would ether not get any response at all or would get the error message that "host couldn't be found" (DNS issue for sure). Reall sad thing is I would have to boot into Windows (2000 Pro), just to get my 'Net back up and running.

I just recompiled my kernel, removing the !Pv6 stuff from it and now everything is back to normal. So far so good. If I still keep having that problem I'll post on the networking forum.

Thanks,
MMYoung

[chesskidd]

noticed the slowness too :rolleyes: , you can just compile the ipv6 as a module right?

how many websites use ipv6 protocol now? if it's really only 1%, I might as well just remove that feature also... :rolleyes:

[Chili5555]

I, too, noticed the slow DNS resolution on my Mandrake 10 Official box. I found a quick and easy solution. I added the following to /etc/modprobe.conf:

alias net-pf-10 off

After a reboot, all was speedy once again.

[hard candy]

Especially the "doubleclick" ads on this website. Sometimes it would take forever for them to load, if at all.
Also, search the How I Did It forum for "86 those annoying ads" and there is a post just recently for using the technique for Konqueror.

[hard candy]

And, for name server use, using IPV6 exclusively,
"To go to a totally IPv6 environment (without IPv4), you'd need to contact name servers using IPv6 cloud. It's easy: you just need to put IPv6 addresses into resolv.conf(5). If you would like to run an IPv6 transport ready DNS server, try running bind9. Example configuration would be like this:

nameserver 3ffe:501:4819::42

There's a working IPv6-ready DNS server running on the above address, so feel free to try it out. "
I just checked with Bellsouth and they said they do not think any of the big ISP's are using IPV6 nameservers yet.

[Cadillac84]

Thanks! I'm still using 2.4.18, but I am soon upgrading to 2.6. I know I would have said, "What can it hurt?" just as you did. So, you have saved me a lot of grief and I do appreciate it!! :cool:

[thedangerouscre]

reply to the question "how many sites use ipv6?". I'm not sure how many i would assume very few do and if they did they would also have to support ipv4. They can't just one day decide to switch to ipv6 and leave the majority of internet usesrs high and dry. If you were concerned about ipv6
i would just compile it as a module and only load it when needed as was suggested earlier. My personal opinion is that if ipv6 causes this much of a problem i don't want anything to do with it. Also if i really need it bad enough I'll just use Winblows since i still keep it for games only because the software companies don't realize or choose to ignore that people like linux.

[schwartz]

Hi!

I use suse 9.1 and disabled ipv6 in modprobe.conf but slow internet again.How can i fix it problem ?

Thanks a Lot!
:(

[hard candy]

First try :modprobe -l | more" and see if the IPV6 modules are listed. Then "modprobe -r modulename" for the IPV6 modules. Also, check /etc/resolv.conf and make sure the DNS servers are listed correctly. You can usually call the IPS and find out which DNS servers they use or get it from a Windows partition if you have Windows loaded anywhere. And Suse may have the modules set to reload each time you boot, may want to check on their sites and see how to disable it.

[mdwatts]

Originally posted by schwartz

I use suse 9.1 and disabled ipv6 in modprobe.conf but slow internet again.How can i fix it problem ?


You may also want to search the Networking forum for i.e. 'slow internet' or 'slow connection' etc. to find other similiar threads on the same problem. You'll find lots of useful suggestions.

[schwartz]

Thanks a lot hard candy for your tips !!

i saw it, Is it correct ??
:confused:

/lib/modules/2.6.5-7.75-default/kernel/net/ipv6/netfilter/ip6table_mangle.ko
/lib/modules/2.6.5-7.75-default/kernel/net/ipv6/netfilter/ip6t_state.ko
/lib/modules/2.6.5-7.75-default/kernel/net/ipv6/netfilter/ip6t_rt.ko
/lib/modules/2.6.5-7.75-default/kernel/net/ipv6/netfilter/ip6t_owner.ko
/lib/modules/2.6.5-7.75-default/kernel/net/ipv6/netfilter/ip6table_filter.ko
/lib/modules/2.6.5-7.75-default/kernel/net/ipv6/netfilter/ip6t_mark.ko
/lib/modules/2.6.5-7.75-default/kernel/net/ipv6/netfilter/ip6t_mac.ko
/lib/modules/2.6.5-7.75-default/kernel/net/ipv6/netfilter/ip6t_limit.ko
/lib/modules/2.6.5-7.75-default/kernel/net/ipv6/netfilter/ip6t_length.ko
/lib/modules/2.6.5-7.75-default/kernel/net/ipv6/netfilter/ip6t_multiport.ko
/lib/modules/2.6.5-7.75-default/kernel/net/ipv6/netfilter/ip6t_hl.ko
/lib/modules/2.6.5-7.75-default/kernel/net/ipv6/netfilter/ip6t_hbh.ko
/lib/modules/2.6.5-7.75-default/kernel/net/ipv6/netfilter/ip6t_frag.ko
/lib/modules/2.6.5-7.75-default/kernel/net/ipv6/netfilter/ip6t_eui64.ko
/lib/modules/2.6.5-7.75-default/kernel/net/ipv6/netfilter/ip6t_esp.ko
/lib/modules/2.6.5-7.75-default/kernel/net/ipv6/netfilter/ip6t_dst.ko
/lib/modules/2.6.5-7.75-default/kernel/net/ipv6/netfilter/ip6t_ah.ko
/lib/modules/2.6.5-7.75-default/kernel/net/ipv6/netfilter/ip6t_REJECT.ko
/lib/modules/2.6.5-7.75-default/kernel/net/ipv6/netfilter/ip6t_MARK.ko
/lib/modules/2.6.5-7.75-default/kernel/net/ipv6/netfilter/ip6t_LOG.ko
/lib/modules/2.6.5-7.75-default/kernel/net/ipv6/netfilter/ip6_tables.ko
/lib/modules/2.6.5-7.75-default/kernel/net/ipv6/netfilter/ip6_queue.ko
/lib/modules/2.6.5-7.75-default/kernel/net/ipv6/netfilter/ip6t_ipv6header.ko
/lib/modules/2.6.5-7.75-default/kernel/net/ipv6/netfilter/ip6_conntrack.ko
/lib/modules/2.6.5-7.75-default/kernel/net/ipv6/netfilter/ip6_conntrack_ftp.ko
/lib/modules/2.6.5-7.75-default/kernel/net/ipv6/mobile_ip6/mip6_mn.ko
/lib/modules/2.6.5-7.75-default/kernel/net/ipv6/mobile_ip6/mip6_ha.ko
/lib/modules/2.6.5-7.75-default/kernel/net/ipv6/mobile_ip6/mip6_base.ko
/lib/modules/2.6.5-7.75-default/kernel/net/ipv6/ipv6.ko
/lib/modules/2.6.5-7.75-default/kernel/net/ipv6/ipv6_tunnel.ko
/lib/modules/2.6.5-7.75-default/kernel/net/ipv6/esp6.ko
/lib/modules/2.6.5-7.75-default/kernel/net/ipv6/ah6.ko
/lib/modules/2.6.5-7.75-default/kernel/net/ipv6/ipcomp6.ko

I check my DNS number and they're same in windo$$.
I try much options for disabled IPV6 in suse 9.1 but its not working.What is it the correct ??

thanks in ADV.

:(

[hard candy]

From a Suse mailing list:
He disables IPv6 like this:

Edit /etc/modules.conf
Change line 339 and 340 from...

alias net-pf-10 ipv6
# alias net-pf-10 off

...to...

# alias net-pf-10 ipv6
alias net-pf-10 off

and then you have to reboot.

[schwartz]

Hard Candy,

I try it in suse 9.1 kernel 2.6.x :

SUSE Linux 9.1 (in connection with Kernel 2.6.x) includes the file /etc/modprobe.conf instead of /etc/modules.conf.

If you want to disable IPv6 on a permanent basis in SUSE Linux 9.1, change the file /etc/modprobe.conf as follows:

Change

alias net-pf-10 ipv6
to

alias net-pf-10 ipv6
install ipv6 /bin/true

i changed it in suse 9.1,But it wasnt working. Any idea?

Thanks a Lot.

[hard candy]

Some more tidbits from Suse mailing lists:
After you make the previous changes to /etc/modprobe.conf, also do this:
I commented out "alias sit0 ipv6"

This is if you are usiig bind:
Maybe your local domain ends in .local ?
Change it. The Bind release notes included in 9.1 says that from now, .local
domain is used as a broadcasting one (I don't know why, but seems there's an
RFC to read). In my LAN, I had same problem until I've RTFM an discovered
this "little" issue. Changed .local domain for another one, and question solved.

This is if you have a router:
I solved the issue by making sure the default gateway is set to my router and if you don't have a local DNS server putting your ISPs DNS server addresses in as your nameservers. I use YaST to do this - Network services .. DNS and Hostname.

[bwkaz]

Originally posted by hard candy
Maybe your local domain ends in .local ?
Change it. The Bind release notes included in 9.1 says that from now, .local
domain is used as a broadcasting one (I don't know why, but seems there's an
RFC to read). In my LAN, I had same problem until I've RTFM an discovered
this "little" issue. Changed .local domain for another one, and question solved. If the person who said this meant .localdomain instead of .local domain, then yes, he's right.

.localdomain has never been reserved for anything in the DNS, especially not as a place to put "localhost". I'm not sure why people (and some distros) keep using localhost.localdomain, but it's bound to break eventually (maybe it just has). You don't strictly need a DNS domain name anyway; just plain localhost should work fine.

[schwartz]

Ok people! I try all that .

thanks a lot!!!

[hard candy]

I just installed Suse 9.1 on an extra partition. Got the same slow resolution. Changed my /etc/modprobe.conf like this: (around line # 325)
alias net-pf-10 off (used to have "ipv6)
# install net-pf-10 /bin/true

Now the pages load before I even press "Go"! :) (of course I have the userContent.css file modified to block the ads as well)

[MMYoung]

I found this information on the Linuxpackages.net site, HERE (http://www.linuxpackages.net/howto.php?page=ipv6&title=ipv6+HOWTO). At the bottom there was this:
5.1. /etc/hosts

The /etc/hosts provides a simple way to make names resolve on smaller networks. The /etc/hosts file specifies an IPv6 and which hostnames should resolve to that IP address. You can add IPv6 addresses to the hosts file, just like you would add IPv4 addresses. This is an example of a /etc/hosts file with IPv4 and IPv6 entries:

# IPv4 entries
127.0.0.1 localhost
192.168.1.1 tazzy.slackfans.org tazzy
192.168.1.2 gideon.slackfans.org

# IPv6 entries
::1 localhost
fec0:0:0:bebe::2 flux.slackfans.org

Please note that "::1" is the default IPv6 loopback.
So I recompiled my kernel to add IPv6, as a module, and added the following to my /etc/hosts

# IPv6 entries
::1 localhost
::1 mypc.athome.net mypc

These entries are identical to the 127.0.0.1 entries that are included by default. I rebooted and now everything is zipping right along.

NOTE: I know that most will say you really don't *need* the localhost entries in /etc/hosts but if you don't need them, then why does Slackware, and most other distros that I have installed, keep putting them there by default? I'm just wondering, not trying to start a flame war or anything.

HTH,
MMYoung

[XiaoKJ]

not true -- mine was as blazing fast as it were before I added ipv6 to it.

and after I added signed up for ipv6 tunneling service (free!) it went faster :D

I don't think ipv6's to be blamed.... maybe its just DNS resolution trouble...

[hard candy]

It is a DNS problem, if IPV6 is enabled, then DNS tries to use IPV6 first to resolve the hostname. After that times out, then it switches to IPV4. Since very few ISP's are using IPV6, there is a delay until the name is resolved via IPV4.
And localhost is used for some processes requiring loopback, such as databases, some xserver processes, and printing.

[hard candy]

Some other tips from the Ubuntu forums on speeding up Mozilla and Firefox:
The latest version of Mozilla includes support for "IPv6" a new form of addressing things on the Internet.

The problem is: Mozilla tries to use IPv6 before it uses IPv4 (IPv4 is the old version). When your Internet connection doesn't support IPv6, Mozilla fails to connect on the first try. In the current version of Mozilla, you can't change this, because of a bug.

To fix this issue follow these steps:
1. sudo nano /etc/modutils/aliases (you can use "su" instead of "sudo" on ohter distros)

Look for this line:
# alias net-pf-10 off # IPv6

Change the line to: (remove the #)
alias net-pf-10 off # IPv6

2. sudo update-modules

And:

editing /etc/modprobe.d/aliases
1. open /etc/modprobe.d/aliases in a text editor with root privilages (for example write 'sudo gedit /etc/modprobe.d/aliases' into a terminal)
2. edit line:
Code:

alias net-pf-10 ipv6

to
Code:

alias net-pf-10 off



modifying about:config
1. write 'about:config' into a mozilla firefox window
2. right-click on the line starting with 'network.dns.disableIPv6' and modify it to 'true'


Not sure if it was necessary (I'm a newbie), but after modifying these things I typed 'sudo update-modules' into a terminal again and now my firefox page loading speed seems to be around the same as in windows

[wrender]

I had the exact same problem with mandrake 10 a while back. I don't know why ipv6 is enabled by default, when ipv4 is still working just fine in the industry.