Network stalls/unreachable

This happens quite often for me: I turn on my GNU/Linux boxen and try to browse the web. Firefox takes a long time start up, then when I enter something like, it takes a while to get there, or even fails to get there. Gmail would be working, then at some point says that the internet isn’t reachable.

In these moments, I ping from console and see this:

PING (2607:f8b0:4005:804::200e)) 56 data bytes

which just hangs there until I kill the command and see something like this: ping statistics —
299 packets transmitted, 0 received, 100% packet loss, time 305134ms

If I ping or ping, it works fine, with times around 10ms.

Currently, Firefox is working, but the pings from console are not. It’s very confusing.

The internet speeds, when working is great, but these network stalls/unreachable moments make the internet annoying.

This only seems to happen with the desktop GNU/Linux boxen, which is hardwired to the router. Mobiles on wi-fi seem to be fine.

/etc/resolve.conf file is autogenerated by netconfig. Is it a DNS issue? Should I add some nameservers to /etc/sysconfig/network/config?

Any ideas? Anything more details I need to provide?


This could be an issue with your router perhaps. Is your router acting as your DNS proxy?

Try something like the following and report back


If you suspect an issue with the router, try configuring an OpenDNS server explicitly.

In this case, IPv6 is not working properly for you.

When I ran into that problem, I would reboot the router and that would fix it. That’s worth trying, but it might not help in your case. Whether it helps depends on the router, your ISP and other factors.

At present, after changing ISP, I don’t have IPv6 access at all – which is a different problem.

When I do this, I do see Server listed as the router:


Non-authoritative answer:
Address: 2001:4998:c:1023::4
Address: 2001:4998:c:1023::5
Address: 2001:4998:44:41d::3
Address: 2001:4998:44:41d::4
Address: 2001:4998:58:1836::10
Address: 2001:4998:58:1836::11

Ah, indeed! This appears to be the problem!

After doing the nslookup, which works fine, I got a list of IPv4 and IPv6 Yahoo addresses. When I ping an IPv4 address from the list, it works. IPv6 hangs.

My router:

IPv6 Connection Type: Auto(SLAAC/DHCPv6) [other options include: Static IPv6, PPPoE and Local-link Only]

Obtain IPv6 DNS Servers automatically [other option is to set Primary and Secondary DNS Servers with IP addresses]

LAN IPv6 address settings, Enable DHCP-PD: On

Address Autoconfiguration Settings:

  • Automatic IPv6 address assignment: On
  • Autoconfiguration Type: SLAAC+Stateless DHCP [other options include: SLAAC+RDNSS and Stateful DHCPv6

YaST2 Network Settings:

eth0 and eth1:

  • Dynamic Address DHCP, DHCP both version 4 and 6 [other options include: DHCP version 4 only and DHCP version 6 only]

Any suggestions from here?

Not really. What you describe seems fairly normal.

Many routers have a built in functionality to monitor internet connectivity, and to restart if that fails. But often they only monitor IPv4 connectivity, and don’t notice problems with IPv6 connectivity.

With my former ISP, the router would find a problem and reset after being up for around 90 days. But it began to have IPv6 problems after around 60 days. So I monitored that myself, and manually restarted when problems showed up.

If IPv6 is completely unreliable for you, then you can disable it in your operating system (Yast/System/Network Settings). If it works for a while, then maybe monitor the router and restart it when there are problems.

Only to restart the router when these symptoms appear, or consider manually configuring DNS to point at a reliable DNS server directly (eg using OpenDNS).

If you are having problems with IPv6,
Then you might try changing your YaST DHCP settings to assign IPv4 addresses only.

Considering the increasing use of IPv6, I would spend some time troubleshooting your IPv6 problems… Would recommend usual steps to run trace route (IPv6) to see if the problem is your own equipment, your ISP or someone else.


I went with:

YaST->Network Settings/Global Options/Enable IPv6 OFF

That certainly resolved my issues and I agree, I need to troubleshoot so that IPv6 works.