Internet connectivity, but no net access - DNS upset?

[speretz]

Wow, thanks guys for all the help.

palladium- the loopback is in my hostname window and my ip settings have been properly setup as far as my router is concerned

hendersj- Downloading wireshark today to see what it tells me, but no I haven't ever really used one.

buckesfeld- Done that already

tuxituk - I think we are on to something, I am getting fragmented pings. When I hit the tuxituk site, it fragments the first couple of times, then it's ok. When I tried opensuse.org, I never got a successful ping.

PING Tux-IT Open Source - BSD and Linux Solutions (87.194.100.100) 1472(1500) bytes of data.
From 192.168.1.254: icmp_seq=1 Frag needed and DF set (mtu = 1492)
From 192.168.1.254 icmp_seq=1 Frag needed and DF set (mtu = 1492)
1480 bytes from 87-194-100-100.bethere.co.uk (87.194.100.100): icmp_seq=2 ttl=49 time=176 ms
1480 bytes from 87-194-100-100.bethere.co.uk (87.194.100.100): icmp_seq=3 ttl=49 time=176 ms
1480 bytes from 87-194-100-100.bethere.co.uk (87.194.100.100): icmp_seq=4 ttl=49 time=175 ms
1480 bytes from 87-194-100-100.bethere.co.uk (87.194.100.100): icmp_seq=5 ttl=49 time=175 ms
1480 bytes from 87-194-100-100.bethere.co.uk (87.194.100.100): icmp_seq=6 ttl=49 time=176 ms
1480 bytes from 87-194-100-100.bethere.co.uk (87.194.100.100): icmp_seq=7 ttl=49 time=175 ms
1480 bytes from 87-194-100-100.bethere.co.uk (87.194.100.100): icmp_seq=8 ttl=49 time=176 ms
1480 bytes from 87-194-100-100.bethere.co.uk (87.194.100.100): icmp_seq=9 ttl=49 time=180 ms
1480 bytes from 87-194-100-100.bethere.co.uk (87.194.100.100): icmp_seq=10 ttl=49 time=185 ms
^C
--- Tux-IT Open Source - BSD and Linux Solutions ping statistics ---
11 packets transmitted, 9 received, +2 errors, 18% packet loss, time 24035ms
rtt min/avg/max/mdev = 175.701/177.648/185.816/3.171 ms, pipe 2

PING opensuse.org (130.57.5.70) 1472(1500) bytes of data.
From 192.168.1.254: icmp_seq=1 Frag needed and DF set (mtu = 1492)
From 192.168.1.254 icmp_seq=1 Frag needed and DF set (mtu = 1492)
From 192.168.1.254 icmp_seq=22 Frag needed and DF set (mtu = 1492)
^C

eth0 Link encap:Ethernet HWaddr 00:1E:EC:71:07:B8
UP BROADCAST MULTICAST MTU:1500 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:0 (0.0 b) TX bytes:0 (0.0 b)
Memory:e8000000-e8020000

lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
inet6 addr: ::1/128 Scope:Host
UP LOOPBACK RUNNING MTU:16436 Metric:1
RX packets:14 errors:0 dropped:0 overruns:0 frame:0
TX packets:14 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:820 (820.0 b) TX bytes:820 (820.0 b)

pan0 Link encap:Ethernet HWaddr BE:A5:CD:AD:8D:16
BROADCAST MULTICAST MTU:1500 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:0 (0.0 b) TX bytes:0 (0.0 b)

wlan0 Link encap:Ethernet HWaddr 00:21:5C:2B:27:6B
inet addr:192.168.2.6 Bcast:192.168.2.255 Mask:255.255.255.0
inet6 addr: fe80::221:5cff:fe2b:276b/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:1263 errors:0 dropped:0 overruns:0 frame:0
TX packets:412 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:458251 (447.5 Kb) TX bytes:193242 (188.7 Kb)

wmaster0 Link encap:UNSPEC HWaddr 00-21-5C-2B-27-6B-32-62-00-00-00-00-00-00-00-00
UP RUNNING MTU:0 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:0 (0.0 b) TX bytes:0 (0.0 b)

Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
192.168.2.0 * 255.255.255.0 U 2 0 0 wlan0
default . 0.0.0.0 UG 0 0 0 wlan0

[nstuart]

Had this same problem, here are a couple of notes:

• Disabling IP-V6 in yast doesn't work, there is a bug out there for it but you need to add a boot option which I can not remember and not at that computer right now.
• Once IP-V6 was disabled, almost everything worked (browsing etc). BUT tools like ssh and wget would not resolve host names, so that brings me to the next point...
• Edit resolv.conf to put in your ISP addresses it should work, did the trick for me! I don't know if its the router or the dsl modem that is causing my issues (netopia modem, linksys wireless router) but it works now.

Hope this helps, just google for the bug above for disabling ip-v6 with opensuse and you should find it.

Also, you can check if it really is disabled by running ifconfig, you shouldn't see any v6 addresses there.

speretz wrote:
> tuxituk - I think we are on to something, I am getting fragmented
> pings. When I hit the tuxituk site, it fragments the first couple of
> times, then it's ok. When I tried opensuse.org, I never got a
> successful ping.
>
> From 192.168.1.254: icmp_seq=1 Frag needed and DF set (mtu = 1492)
> [snip] PING opensuse.org (130.57.5.70) 1472(1500) bytes of data.

i'm not sure this is your problem, but you try the following and then
back out the changes if it doesn't work:

determine and set MTU:

so, pick something smaller than 1492

ping -c 1 -s 1492 -M do google.com

keep decreasing until there is no fragmentation


then to set, become root and do

ifconfig eth0 mtu 1490

TWO notes on that command:
-use 1490 *or* whatever you learned was the highest no frag MTU
-command assumes only one network card (0)

live with it a while....to make that permanent:

add/change MTU='1490' in /etc/sysconfig/network/ifcfg-eth0 (*IF* it is
ethernet card zero)

*OR* gui:YaST > root pass > Network Devices > Network Card > Overview
(tab) > Configure > General (tab) and change/fill in the MTU blank
with 1490, then Finish

*OR* YaST => System => /etc/sysconfig Editor => Hardware => Network =>
<Choose interface> (in this case eth0) => MTU

--
palladium
Have a lot of fun..

[michael_cheah]

Originally Posted by nstuart

Had this same problem, here are a couple of notes:

• Disabling IP-V6 in yast doesn't work, there is a bug out there for it but you need to add a boot option which I can not remember and not at that computer right now.
• Once IP-V6 was disabled, almost everything worked (browsing etc). BUT tools like ssh and wget would not resolve host names, so that brings me to the next point...
• Edit resolv.conf to put in your ISP addresses it should work, did the trick for me! I don't know if its the router or the dsl modem that is causing my issues (netopia modem, linksys wireless router) but it works now.

Hope this helps, just google for the bug above for disabling ip-v6 with opensuse and you should find it.

Also, you can check if it really is disabled by running ifconfig, you shouldn't see any v6 addresses there.

The boot parameter is ipv6.disable=1

For more reference look at this bug
https://bugzilla.novell.com/show_bug.cgi?id=539869

[hendersj]

On Wed, 04 Nov 2009 14:06:01 +0000, speretz wrote:

> hendersj- Downloading wireshark today to see what it tells me, but no I
> haven't ever really used one.

If you have a background in IT type work, then you should be able to pick
it up pretty easily - though it is a complex piece of software.

Basically what you'll want to do is capture (make sure you've selected
the correct interface - you will need to run it as root) all traffic to
and from your machine. Start the capture, do what's failing, and then
stop the capture. Repeat these steps in the situation where the
operation succeeds. That'll give you something to compare to.

Chances are that you'll see some sort of error condition on the not-
working trace (Wireshark is really good in that it makes errors really
visible - whether it's a bad reply, a corrupted response, or packet
loss), and that should help us figure out what the problem is.

Jim

--
Jim Henderson
openSUSE Forums Moderator

[speretz]

PROBLEM SOLVED!!!!

Thanks for the wireshark tip. It looks like a really cool program that I will be able to use a lot.

When I was told to google the boot command to disable ipv6 I found a suse help file to disable ipv6 and it went through disabling in the /etc/sysconfig editor. I followed the KDE instructions even though I am using Gnome and BIGNO, all is well.

Now time to conquer my compiz issues... again

[speretz]

NEVERMIND

I cannot connect to repos. Any of them. I can browse to them in firefox without a problem, but not with yast. I ran wireshark on it and it tells me definitively that it cannot resolve download.opensuse.org, but it is only for yast. I am lost...

[hendersj]

On Thu, 05 Nov 2009 02:06:02 +0000, speretz wrote:

> PROBLEM SOLVED!!!!
>
> Thanks for the wireshark tip. It looks like a really cool program that
> I will be able to use a lot.

Great news, and I'm glad that helped. :-)

Jim



--
Jim Henderson
openSUSE Forums Moderator

[hendersj]

On Thu, 05 Nov 2009 02:36:01 +0000, speretz wrote:

> I ran wireshark on it and it tells
> me definitively that it cannot resolve download.opensuse.org, but it is
> only for yast. I am lost...

Are you seeing responses from the DNS server?

Jim



--
Jim Henderson
openSUSE Forums Moderator

[buckesfeld]

* speretz,

maybe you missed a place where IP V6 needs to be disabled. With openSUSE 11 it should be as easy as disabling it in the NIC configuration in Yast.

Uwe