strange ping problem ( lan / router / wan )

[CapNemo]

hi all :)

i just downloaded knoppix 3.7, and booted from cd (nothing installed on hdd, yet)
now i'm trying to connect the linux box to my lan and thru my router to the wan.

- the router ( from SMC ) has a default ip address of 192.168.2.1
- the linux box uses a wired connection ( normal cat5 cables, with a switch in between the router and the box )
- dhcp is disabled, all clients use fixed ip addresses
- i used "knoppix nodhcp 2" at the knoppix boot prompt

if i assign an ip to eth0 and set default gateway, broadcast and nameserver, the following happens:
- the linux box is able to ping itself
- the linux box is able to ping other boxes in the lan
- other boxes are able to ping the linux box
- other boxes are able to ping the router
- the linux box CAN NOT ping the router
- the linux box CAN NOT connect to the wan
- if the linux box pings broadcast ( 192.168.2.255 ) only the linux box responds
- (not sure on that, but i guess the linux box has an MTU of 1500; the router of 1492, does that matter in any way, if yes, how do i change it? )

what do i need to do to be able to ping the router, and connect to the wan?

tried to use the search function, but found nothing yet...

thanks in advance :)

Nemo

[Harry Kuhman]

You might want to tell us all of the settings that you made with netcardconfig.

I understand that you have static IP addresses on all of the other systems (and I understand why, even though this is a pain, that you would want to do this with an SMC router). However, even if all other devices have static IP settings, the router can still run DHCP (just make sure that the range of addresses that it hands out does not contain any of the static addresses. Let it hand out 220 to 230 for example). If you do that can Knoppix connect to it, configure with DHCP and talk normally? (Yes, you may still want to give it a static setting, but this test should tell us a lot and looking at the configuration might show what is configured differently.)

It sure doesn't make any sense that you could ping other boxes on the local network but not the SMC router. Can you ping other computers plugged into different router ports, or can you only ping computers that share the switch before the router? Have you tried plugging the Knoppix box right into a router port to take the switch out of the picture (not that I can imagine anything the switch could be doing wrong in this case)?

[CapNemo]

hey's ;)

you're fast, wow :)

my settings are:
- router:
-- ip: 192.168.2.1
-- dhcp off
-- acts as default gateway and nameserver

- linux box:
-- ip: 192.168.2.x (tried several)
-- dhcp should be off, at least it said so at boot time ;)
-- set default gateway to 192.168.2.1
-- set broadcast to 192.168.2.255
-- set nameserver to 192.168.2.1

- other boxes:
-- ip: 192.168.2.y (other ip addresses, of course ;)
-- dhcp off
-- etc...

if i do network-setup it tries to enter all values, sets some routes and still remains "offline"...

any ideas?

thank you,
Nemo

EDIT:
it's not a 3com nic, btw ;)

[Harry Kuhman]

.....any ideas?
Nope, same questions as before. What happend if you turn on DHCP in the router (this will cause no problems for the other systems that configure themselves statically, you can mix both on a system as long as you do not try to hand out the static address range) and then boot knoppix without the cheat code that turns off DHCP? Have you tried going right into a router port and bypassing the switch? You can post the actual 192.168.2.x addresses, there is no security issue in us seeing them. No, under normal conditions it shouldn't make a difference, but just maybe something can be spotted from the real data rather than the condedsed sanatised data (I caught at least one other problem that way some time ago in these forums, user knew better but was making a subconscious mistake that he just couldn't see until it was pointed out to him).

Beyond this you might want to try running ethereal and sniffing your packets to see just what is going out on the wire and if anything looks dufferent about a ping to the router than to another local computer.

[CapNemo]

i tried what you suggested and enabled dhcp on the router.
knoppix couldn't assign an ip address while booting, and network-setup couldn't either later on.
if i enter the values manually again, i get the same results.

i can ping different boxes, wired and wireless, not only those connected to the same switch.

/me scratches head ;)

Nemo

EDIT:
you're really fast *g* :)
i cannot connect it directly to the router (it's a cable mess already, and i cannot move the router or the box atm.. but all other machines using that switch (4 port) are working normally...
tried to use tcpdump, only message i see while trying to ping is "arp who-has 192.168.2.1 tell 192.168.2.x", does it need to know the routers mac address too?
i'm going to try ethereal now...

[Harry Kuhman]

i tried what you suggested and enabled dhcp on the router.
knoppix couldn't assign an ip address while booting, and network-setup couldn't either later on.
if i enter the values manually again, i get the same results.Nemo
By network-setup I hope you mean netcardconfig, but I wanted to ask. I think were's going to have to be very exact on or terms and keywords if we are going to track this down and not make assumptions about what the other is saying.

With the router's DHCP enabled and Knoppix booted without the nodhcp cheat code, try the two following commands from a shell "sudo mii-tool -r" and "netcardconfig". When Netcardconfig starts, take the YES option. Please post back the exact text of any errors.

I'm still hoping that ethereal might be giving you some insight, as I do have doubts that the above will tell us that much. Certainly your card is working fine if it can ping other local systems. It might help to post back the exact text of the result of the ifconfig command. You could also use ifconfig to change your mtu if you really think that could be an issue, but I don't see how it could be for a simple ping. And you might want to look at the man page for ifconfig for other inspiration.

[CapNemo]

...
You can post the actual 192.168.2.x addresses, there is no security issue in us seeing them.
...
*lol*
i used .x because i tried several different addresses with the same result.
i assigned my normal boxes adresses in the range of .10 to .99 and tried these at the linux box:
.19 <- not used on other boxes
.111 <- far away from the other range, just to be sure
.200 - .230 <- the router should hand out these with dhcp, the linux box couldn't get one, for whatever reason...
.210 <- assigned manually, while the router was dhcp enabled

thanks for your patience :)
Nemo

[Harry Kuhman]

EDIT:
you're really fast *g* :)
i cannot connect it directly to the router (it's a cable mess already, and i cannot move the router or the box atm.. but all other machines using that switch (4 port) are working normally...
tried to use tcpdump, only message i see while trying to ping is "arp who-has 192.168.2.1 tell 192.168.2.x", does it need to know the routers mac address too?
i'm going to try ethereal now...

Please quit editing to add information, as I don't get any notification that there is more information posted that way. Just add a new post to the thread.

Also, please stop the 192.168.2.x stuff. This is where it really matters and I can't tell what is hapening when you make the changes to Xs. All 192.168 addresses are completely local and cannot be reached across the network, so there is no security issue here and no reason to hide local addresses.

ARP (address resolution protocol) is one of the things that you see when you sniff the wire. It seems that ARP is working if other pings are getting to you and back to you across the network, but since we have a situation that makes no sense here I don't want to just assume that. You should see different ARP packets. You will not see other systems respond to the router since you are on a switch rather than a hub (although you could see these packets with ethereal on the other system, there is a windows version as well as a linux version).

What will happen during ARP is an exchange of IP and MAC address information. This is how the system matches up IP to MAC addresses.

For that matter, have you tried to boot the Knoppix CD on any of the other systems? Is this problem local to this one PC, or does it exist when any PC tries to ping the router from Knoppix?

[Harry Kuhman]

The last post about 192.168.2.x was written before I saw you response. Thanks, but lets just try to use real addresses, just in case something shows up somewhere when we do.

[CapNemo]

sorry, was used from other boards to use edit, wont do any more.

the router is dhcp enabled now, and should hand out addresses in the range of .200 to .230
restarted knoppix without any "cheatcodes", dhcp enabled.

did the commands like you stated it, no error messages on "sudo mii-tool -r"
if i run netcardconfig i get the following errors:
--- snip ---
Sende DHCP Broadcast von Netzwerkkarte eth0eth0: link up
Operation failed.
Fehlgeschlagen.
Eingabetaste zum beenden.
--- snip ---

translated to somewhat like:
--- snip ---
Sending DHCP Broadcast from nic etc0etc0: link uo
Operation failed.
Failed.
Enter to finish.
--- snip ---

cannot try on other machines atm, they're in use or wireless, going to try later on.

again, thanks a bunch :)
Nemo

[Harry Kuhman]

translated to somewhat like:
--- snip ---
Sending DHCP Broadcast from nic etc0etc0: link uo
Operation failed.
Failed.
Enter to finish.
--- snip ---

cannot try on other machines atm, they're in use or wireless, going to try later on.
Ok, thanks for the translation, I was heading for the babblefish as I saw that you had included it. I'm really stumped on this, it makes absolutely no sense since you can ping other systems, even ones that you are reaching through the router (like the wireless ones).

It seems we have 2 problems here, you can't ping the SMC router, but only from the Knoppix box. And you can't get to the Internet through the router although you can get to other local machines going through the router.

OK, here's yet another strange experiiment to try:
Ping 66.220.1.171 from Knoppix.
That's the IP address of www.knoppix.net. If you can ping it but not www.knoppix.net then we have some sort of name resolution issue (along with the router ping problem). If you can't ping it then name resolution isn't the problem but it's even more of a mystery why you can ping local addresses but not the router or Internet addresses.

If the ping works (and maybe even if it doesn't) try putting the IP address 66.220.1.171 into the Konqurer address line and see if you can get to Knoppix.net that way (I just did it in Knoppix and it works for me).

I'm still hoping you can learn something from ethereal, as I'm quickly running out of ideas. Since you have not been able to run Knoppix on the other systems, have you ever or are you able now to run Windows or anything else non-linux that you could try to ping the router with on the "failing system"?

And you might tell us what the exact model and even firmware revision of the SMC router is. I'm currently on a Dlink router, but have an SMC wireless router here that has worked fine with Knoppix; if they are the same model I might even hook up the SMC again. Tell us all you can about the Knoppix computer too. CPU, memory, make of NIC, and plenty of other things that shouldn't be important. There is something that we are missing and too much information is far better than missing the key fact. For that matter, what's the make and model of that switch?

Please post back any progress (or even lack of same) as I really want to follow this and understand what you are seeing.

Harry

No more fast responses for me, I'm going to dinner.

[CapNemo]

hey's again ;)

i tried knoppix on another machine (same switch) and netcardconfig worked without problems.
the other box was able to ping the router and could connect to the wan too.
ping was working for internal and external ip addresses, resolving of hostnames was working, and www was working too.

using ethereal on the "original" box, displayed not that much useful information, besides that it looks like the "arp who-has 192.168.2.1 tell 192.168.2.111" fails (no response to the request)
i tried to add the routers lan mac address manually using arp -s but that didn't change a thing.
i can ping other boxes, other boxes can ping the linux machine, i cannot ping the router, or wan ip addresses.

could it be some "driver" issue?
the box has only a cheap nic installed, but it works fine when booting windoze...

/me scratches head some more ;)

and thanks ;)
Nemo

[CapNemo]

the "stats" about my hardware are:

- router:
-- SMC2804WBR V.2
-- Runtime Code Version: V1.00.001
-- Boot Code Version: V0.00.06

- "linux" box:
-- pentium3 866 mhz
-- 384 mb rambus
-- cheap nic, "NationalSemiconductor"(?)

- "working" box:
-- pentium4 3.2ghz
-- 1024 mb ram
-- asus p4p800-e deluxe mainboard
-- nic on board

dunno if that information is of any use, except for the nic maybe...

\\//,
Nemo

[CapNemo]

missed some information in the post before...

cant remember the brand of the switch, it's a kinda "standard" one, 4 ports + 1 uplink.
all other boxes using that switch (2 pc's and a "multimedia device") are working just fine.

both, the "working" and the "linux" box are using fasttrack raid controllers, onboard for "working", as pci card for "linux".

would any more information be useful?

Nemo

[Harry Kuhman]

Have you tried to ping the www.knoppix.net IP address that I gave you? What were the results?

I may have some insight, if this is it you're not going to like yourself. I hope that you at least are willing to post back and not leave me wondering. SMC routers have a feature that lets you build a list of MAC addresses that the router will respond to. Have you populated that table with the MAC addresses of the other systems, turned the feature on, and then forgotten about it? I think that it might do exactly as you have describe if that was the case.

[CapNemo]

hey's again ;)

i tried to ping both the hostname and the ip address, it didn't get thru.
and yes, i've got mac access control enabled, but the mac address displayed by ifconfig matches the one entered in the router.
if i'm booting windoze on the same box without the knoppix cd the network connection works fine.

if i'm using the knoppix cd on another box (same switch) it's working too.
even booted without cheatcodes, killed pump, ran netcardconfig et voila, there's the connection.
pining the knoppix.net hostname and ip address is working then too, and konqueror displays the page properly.

i guess i'll try changing the "linux box" nic, maybe that'll do the trick...

\\//,
Nemo

[Harry Kuhman]

if i'm booting windoze on the same box without the knoppix cd the network connection works fine.
if i'm using the knoppix cd on another box (same switch) it's working too.
even booted without cheatcodes, killed pump, ran netcardconfig et voila, there's the connection.
pining the knoppix.net hostname and ip address is working then too, and konqueror displays the page properly.
i guess i'll try changing the "linux box" nic, maybe that'll do the trick...
Wow , I did not expect this response. I really thought it was going to be the nic table in the SMC.

So so far we know Knoppix works fine into your router (and switch) when on another PC. And Windows on that PC can connect. I do know of a problem where Windows can use a NIC but Knoppix can not use it (any longer). That problem is talked about in these two threads (amoung others): http://www.knoppix.net/forum/viewtopic.php?t=2117&postdays=0&postorder=asc&start=0
and http://www.knoppix.net/forum/viewtopic.php?t=2164&postdays=0&postorder=asc&start=0 . But this can not be your problem, since you are able to ping other local systems and they can ping your Knoppix box, even running the pings through the router. The above problem completely stops the NIC from working (kills speed and duplex negoiation). What a mystery!

If, as it sounds, you are using the SMC NIC table to control access, you might want to disable that feature in the router for a few minutes and see if the Knoppix box can ping the router and access the Internet then. This just sounds so much like it could be the NIC table, although the fact that Windows on the same box can use the router makes no sense with that theory. Still, it's a very easy test to do. You might want to look very closely at the packets with ethereal too, to be certain that the NIC is reporting the same MAC address on the wire when it is running Knoppix and Windows. Even look at a Windows ping packet and a Knoppix ping packet and see what is different between the two.

I can't argue against changing the NIC, although turning off access by MAC address is a simple to do first step (the NIC might well still be the fastest way to "fix" this though). I just hope we end up learning enough to figure out what the problem is. If the NEC swap does reesolve it for you, consider trying that NIC in a different computer and see if Knoppix still fails with it (either leave the old NIC in the table or enter it again when you do the later test). And don't forget to put the MAC of the new NIC in the table, or turn off access control by MAC address long enough to test the new NIC.

It also might come down to having to manually reset the SMC router and reconfigure it. But to be honest, I can't come up with any state that the SMC would get into that would allow it to work with Windwos but not with Knoppix, on this one computer only.


Please keep posting your progress.

[CapNemo]

hey's,

congrats on the 1000 ;)
as far as i can see till now, you're doing a great job and i really appreciate your suggestions and ideas :)

i'll disable the mac access control later on, and if that doesn't resolve it i'll even try other things like enabling dmz host etc, i'll keep you posted...

thanks a lot :)
Nemo

[Harry Kuhman]

Nemo, how about a status update?

[Harry Kuhman]

Nemo, you still there?

[CapNemo]

hi again,

sorry for that delay in my follow up, "real life" problems kept me from messing around with linux the last couple of days...

first of all, i'd like to thank you for your patience, second is: it's working now. :)
it WAS the mac access control, after all.
what i didn't figure out until really disabling it is the following:
apparently knoppix changes the mac address at one byte, only for that pc.
"win": 00:09:6B:... -> "knoppix": 00:09:5B:...
looks like i've overseen that while i checked first.
what i don't understand is, why knoppix changes the mac ( or does windoze, and i didn't notice it yet? ), and why it happens only at one pc, as the other box i tested it on is working fine, using both win and linux.

\\//,
Nemo

[Harry Kuhman]

it WAS the mac access control, after all.
what i didn't figure out until really disabling it is the following:
apparently knoppix changes the mac address at one byte, only for that pc.
"win": 00:09:6B:... -> "knoppix": 00:09:5B:...
looks like i've overseen that while i checked first.
what i don't understand is, why knoppix changes the mac ( or does windoze, and i didn't notice it yet? ), and why it happens only at one pc, as the other box i tested it on is working fine, using both win and linux.
Thanks for the feedback Nemo. And that's a very interesting report. I can tell you that I never have seen a difference between Windows and Knoppix MAC addresses, and I use the MAC address to force IP address assignments with my Dlink router, likely for the same reasons that you are using static addresses on your system. My router would and does assign a different address if the MAC was "new", so I can safely state that Knoppix does not change my MAC addresses. I know Linux can change the MAC address if told to, but have never seen it happen without being told. If anyone has more information or insight on this I would really welcome the feedback.

Gald it was fixed. Sure didn't make much sense when we started the discussion, but it was resolvable.

[pureone]

i have had this happen to me a few times.

i run a router with wifi access so i make sure mac access is on at all times. and i have noticed that sometimes knoppix does create a differnt mac address. why i have no idea but i know that it does happen