invalid eth0:1 interface and strange pan0 interface
 

To get Internet access I use with my ThinkPad T60 Slackware 13.1 box ASMAX AR 1004g modem-router.

[EDIT]
11th Oct 2010 at 03:00
Formerly I used binary phone line with a modem. In that configuration my modem provided Internet access on ppp0 interface leaving eth0 interface free for an internal network. My new analog modem-router provides the Internet access by default on eth0 interface. In such case I lose the internal network. After some researching I managed to find the configuration of the modem-router and the system allowing to use in the same time internal network on eth0 interface and Internet access on pan0 interface. It wasn’t my intention to use pan0 interface and I wonder how my machine can communicate with modem-router using Bluetooth interface.

Below I describe how I found that configuration and I ask three questions related to that problem.
[/EDIT]

[EDIT]
15th Oct 2010 at 16:05
The above problem was solved in posts from 2 to 5 but a new problem arose in posts from 4 to 7. It concerns the validity of my LAN and WAN network configuration. So the thread is still alive.
[/EDIT]

The first scenario – router offers private IP

In default configuration ASMAX offers IP number from 192.168.1.* private class. That IP address is invisible from Internet. Moreover in such a situation I lose my private network:

# ifconfig eth0
# route

The second scenario – router offers public IP

Fortunately ASMAX Advanced Setup WAN configuration offers PPP IP extension option. After switching it to on ASMAX starts to offer IP number from public class. That IP address is visible from Internet. My former modem assigned public IP number to ppp0 interface so I still had local network assigned to eth0 interface. ASMAX modem-router assigns that public IP number to eth0 interface. So in that case I lose my private network too:

# ifconfig
# route
In both the above scenarios I enabled DHCP in the configuration file:

/etc/rc.d/rc.inet1.conf:

The third scenario – invalid eth0:1 interface and strange pan0 interface

After some researching I found that it’s enough switch off DHCP and set local IP to get private network working:

/etc/rc.d/rc.inet1.conf:
In such case dhcpcd tries to run Internet connection during boot procedures using eth0:1 interface but it fails:

/var/log/messages:
In result the full output of ifconfig looks like this:

# ifconfig
# route
Now when I want to get Internet wired access I run dhcpcd command without any options:

# dhcpcd
In result I get an Internet access on pan0 interface keeping in the same time local network on eth0 interface:

# ifconfig
# route

My three questions

Searching Internet I found two information: eth0:* is for network aliases and pan0 is a Bluetooth interface.

My machine has Ethernet, WiFi and Bluetooth devices. My modem-router has wired and wireless interface (but no Bluetooth).

So I ask you three questions:

1. Why dhcpcd tries eth0:1 interface during boot procedures?

2. How can my machine use pan0 interface to establish wired communication to my modem-router?

3. Should I worry about it?

I don't know, and I don't think it is important.

If pan0 is the name of your Bluetooth interface, than you cannot use it to get wired connection to router. You cannot connect to router via Bluetooth at all.

If it works - you can leave it as it is. You write:
But I wonder if you really have internet connection via pan0 interface?

-------------
I would just connect to router via WiFi (wlan0) and to LAN via eth0.
-------------
KISS rule(z)

Thanks for calming me down.

I don’t know if pan0 is the name of my Bluetooth interface in the situation described above. After some reading I know it’s the name of Bluetooth interface in general. In my case pan0 seems to communicate with my router. I wonder how it’s possible.

Thanks once again.

So there are two of us wondering about it.

Three programs – dhcpcd, ifconfig and route – report pan0 interface usage. The speed of Internet connection through pan0 is up to 10 Mbits/sec. After I switch my router off the Internet connection ends. So it seems pan0 co-operates with the router in my case and I wonder how it’s possible.

I tried that at the very beginning. When I run wlan0 Internet connection it throw my local network away from eth0 interface.

I know KISS rule – just see my Slackware desktop. I started with a very basic configuration. Because it didn’t work I tried different options. Finally I found the method to get LAN and WAN at the same time. It isn’t simple but it seems that it’s the simplest way of get both of them in my case.

Now I intend to buy WiFi and Bluetooth devices for my old ThinkPad T40 to make possible Internet connections working together with the local network on that machine.

Your post was helpful. Thank you once again.

I still don’t know how it’s possible for my machine to establish Internet connection to my router via pan0 interface.

Since it works - it seems that pan0 interface name is assigned to your wireless card, not to the Bluetooth adapter, or you will not get the connection to your router. You can try to get more info from iwcofig pan0 to see if this is in fact wireless interface.

There are few things to note on the output you previously posted:
1. on pan0 you have RX bytes:0
2. route reports eth0 as default route
So unless you have some specific configuration (proxy?) you should not have internet access via pan0. Check it.

Also, unless you have a good reason, the natural way would be to connect your modem-router (preferably by wire) to whatever network device creates your LAN (switch?) and share the internet connection for all LAN/WLAN workstation. Then you would have only one network connection from each workstation. It is much easier to manage, and you can grant/restrict internet access to selected workstation if you need.

Be careful with forwarding public IP to a machine behind the router. Also note, that you cannot add second workstation (e.g. laptop) connected to internet with such configuration. I'd recommend re-organize your topology.
If you need help - write more about your LAN device and confirm that you do not want or cannot connect router to LAN.

pan0 interface appears when I establish wired connection to Internet so it isn’t assigned to my wireless card. In such circumstances wicd-curses reports “wired-default” connection. The command you suggested reports there isn’t wireless connection too.

# iwconfig pan0
That’s right.

That’s right.

Finally I decided to switch Bluetooth off and try to run dhcpcd command:

# dhcpcd
# ifconfig
# route
As it turned out both WAN and LAN work without Bluetooth and pan0 interface:

# ping -c 3 192.168.1.4
# ping -c 3 google.com
Thank you for guiding me to the solution of that problem. I was sure Bluetooth plays some role in that process. Meanwhile pan0 entry in ifconfig output means nothing. I was deluded by meaningless information displayed by the program.

I’m afraid I don’t understand your suggestion. As far I used three machines connected to the router. Each of them sees two others through local network.

I’m able to connect to Internet the first machine using wire of wireless method. Wired method I described above. So far I suspected it uses somehow Bluetooth device. Now I see pan0 interface is irrelevant.

The second machine doesn’t connect to Internet. So far I thought the problem is caused by lacking of Bluetooth device. Now I see I have to find some new reason of such state of affairs.

I performed a few tests and I think I’ll start a new thread soon.

Is forwarding public IP to the machine behind the router insecure even when I use iptables-based firewall?

I decided to use that method because when I used private IP it overrode my local IP disabling usage of the local network. Moreover such programs as MLDonkey worked in the configuration based on private IP with low bandwidth.

I’m still not sure I understand you.

I have analog phone line. Modem-router is connected to that line by wire. Three machines are connected by wires to three Ethernet ports in the router. Each machine sees two other in the local network. The first machine connects to Internet as I described above. The second machine refuses to connect. If I don’t find the solution I’ll describe it in a new thread.

Thank you very much for your last post. You helped me to resolve one of my problems. Now I know I don’t have to buy Bluetooth device for the second machine.

I’m sorry I reply after two days of delay. In the meantime I struggled with some other problem.

Good, you simplified the situation :)

OK, I got the impression, that you had some large LAN already working, and now added modem-router to it.
But you have just one modem-router and three workstations, nothing more, right?

Yes, it is less secure. But you can do it if you want.

When you forwarded the only public IP to one of machines, other machines have no chance to get a route to WAN (all traffic must be routed through a device with public IP).

That's what port forwarding on router is meant for.

There is one more thing to check and probably simplyfy:
Dhcp offers 77.25.89.58 for eth0, yet ifconfig reports inet addr:192.168.1.2. It looks like you have 2 addresses assigned to eth0, and that would explain why you had some messages about eth0:1.

To make WAN available to all machines you must get back to the configuration with router having public IP, other machines having private IP numbers. Start from the beginning and do it step by step, all on wired connections, either all on DHCP configured on router, or all on static IP. Try to ping not the other machine on LAN, but your router first, then the default gateway configured on router (the first machine outside your LAN), then your DNS server. Then add next machine. This must work.
Cheers!

That's right.

In fact I did it already. I started with Alien’s Bob Easy Firewall Generator for IPTables using Internet interface +. Then I added to it the rules for WWW, SSH, aMule, MLDonkey and local network. By default only local network rules are switched on. The other sets of rules I switch on when I need them. For example I switch WWW rules on when I want to give someone the access to my home page stored on my machine. This is the reason for which I need a public IP address.

I’m aware that using public IP is less secure than using private IP. On the other hand my router offers dynamic IP. From my point of view it’s more secure than static IP because it makes harder to someone to collect the information about my machines.

I’m starting to understand you, though I have the impression that I had two parallel Internet connections via router before I upgraded Slackware on my second machine to the newest version. Moreover with the older Slackware version on the second machine I didn’t notice the problem described in kernel: dhcpcd segfault at... I think I should to move back and try it once again from the beginning.

One more doubt solved. Thank you.

Now I just reply to your post. I’ll try your advices later. After that I’ll report here the results. At the moment I have some big trouble concerning my second machine. I reported it in kernel: dhcpcd segfault at... Fourtunately I have the third machine. I installed on it trimmed down Slackware 13.0 an I could use it for the tests of the Internet connection. On the other hand my second machine worked fine with Slackware 13.0 and started to fail with Slackware 13.1. So I think the better starting point is to downgrade Slackware on the second machine to 13.0 and test everything from the very beginning. As I see I have a lot tests to perform.

Thank you very much for your constant assistance, dr_agon.

I looked at your other thread. I would just leave the dhcp and put everything on static IPs.

You are welcome to ask more if you want.

Finally I managed to force both my machines to connect to Internet (not in the same time). I described it in the third post from kernel: dhcpcd segfault at... thread. Now I'll try your and emage's tips concerning sharing of Internet connection. I close that thread as solved. After finishing the work I'll report here how I achieved the solution.

[EDIT]
At the moment I stated I don't need to share Internet connection. It's enough for me to connect to Internet at the same time using one of my machines. So my problem is solved completely. Thank you dr_agon for your companionship. Best wishes.
[/EDIT]