Network Manager problems with sharing connection [SOLVED]

[LIsLinuxIsSogood]

Hi, I am wondering what I could be missing, and whether or not the network manager software, with connection-sharing use flag enabled is supposed to work correctly without any changes to routing tables.

Problem is after following the wiki to a "t" about setting NetworkManager and creating the interface just like I have countless times on other machines, and the interface does activate and the connection is active (able to be pinging the desktop computer from connected laptop) but when trying to reach the internet no luck. Any ideas why? I thought maybe the firewall setting on my box...butI'm not too familiar with that. I'm happy to provide more info if needed.

[Tony0945]

Name resolution? Is a nameserver set? Try "ping 8.8.8.8" if that works and "ping www.gentoo.org" doesn't then I'm betting a hundred bucks it's DNS resolution. If "ping 8.8.8.8" doesn't work then packets are not going out or not coming back or coming back but not being forwarded correctly. It could be firewall, it could be router configuration, it could be a lot of things, but first lock down the problem set.

[LIsLinuxIsSogood]

Tony0945, thank you for your help. It appears that my description of the problem was missing this fact but the host that shares the connection CAN connect to the internet, using either IP or name resolution. It is the second host which has the problem. However I now have noticed yet another problem with the first computer that it seems to disappear from the network from specific hosts at times and is unreachable unless I can gain access to the shell and ping in reverse to whichever other machine and then it will be able to connect to it. What is this new problem about and is it possibly related to the issue of NetworkManager the service I am running for networking? Would trying without the use of NetworkManager be wise for a next troubleshooting step? To connect to the internet then I would need the hardware, driver, and some commands for connecting to the wifi (I haven't done this in a while since NM does take care of it).

What else might be an efficient way to troubleshoot the two issues, which are:

1) Network Manager internet sharing activates but does not "forward" or "route" stuff to the internet

2) Sometimes the machine disappears from certain other hosts on the network

UPDATE: After restarting the machine it appears that item #2 has corrected itself, so maybe the only thing I can think of is potentially some issues with NFS that caused it.

[Tony0945]

I use netifrc instead of networkmanager so I can't help with that.

loose connections? bad cables?

[LIsLinuxIsSogood]

Yeah, you're probably right or at most it is maybe an issue with router or firewall that can be figured out with some minimal exerting of effort if I choose to repeat the setup but for now it doesn't matter too much since I have wifi capability on both devices. Thanks for the suggestions. Marking as SOLVED.

[Hu]

When you follow steps on a Wiki, please provide a permanent link to the article you used. Some readers may not be inclined to track down the article, and even those that are might be misled if the article was revised after you read it.

For this problem:

• Which machine is connected to the upstream router? Which is connected to the system using NetworkManager to share? I think I understand the answers to these from the prose, but it is better to have you state it explicitly.
• Designate the system connected to the upstream router as the connection-provider. Designate the other as the connection-consumer. What commands did you run on the connection-consumer that should have worked, but did not? In what way did they fail?
• Is IPv4 forwarding enabled on the connection-provider?
• What netfilter rules are loaded on each host? Use iptables-save -c to see them.