Author Topic: Can access internet but not network or router?  (Read 3516 times)

jrsy85

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Can access internet but not network or router?
« on: March 05, 2008, 06:12:50 am »
Hi Guys,

I know this is weird but i'm having the opposite trouble of a lot of people, i can access the internet over my wireless router but i cannot actually ping the router or any computer on my network. i have a speedstream adsl modem plugged into a tp-link wireless router. i can ping the adsl modem but not the router??? any thoughts on how i can access the network, i would like to access my media server.

I am running linuxmce 0710 Beta 3 on a HP NC8000 laptop

Thanks :)
Joel

orionsune

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Re: Can access internet but not network or router?
« Reply #1 on: March 05, 2008, 10:36:28 pm »
Sounds like ICMP replies are disabled inside your wifi router.  This is a very common option, and very common to default to "disabled" also.  Pinging shouldn't matter anyways, just because your not getting a ping reply doesn't nescessarily mean your network isn't working.  Although you did mention not being able to ping other machines, that again can also be an option in the router.  I have seen an option before that said something along the lines of "Isolate each computer [yes/no]"   I don't remember which brand had that option, I vaguely remember calling it a piece of shit brand when I did play with it, just can't remember the name.

Don't forget the typical stuff, turn off all firewalls (because your router is the access point and it has a firewall, keeping firewall turned on the individual machines is just plain redundant.)

Thorough check all the options in your wifi router, if you see an option you don't understand, google it.

To clear this up a little, what does your wifi router have to do with linuxmce?  I'm not being a smartass, i'm actually honestly trying to figure out if your having a problem BECAUSE you installed lmce, or if this problem is unrelated to installing lmce....
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jrsy85

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Re: Can access internet but not network or router?
« Reply #2 on: March 06, 2008, 01:00:36 pm »
I am part way through figuring this out, I had my wireless router as my external interface and my 10/100 as my internal. i have a wireless router i use as my DHCP server that my 4 windows machine attach to it. how can i set linuxmce to just access the router and beome part of the network, i don't want it to take control and become dhcp. i just want it to connect to the wireless router automatically, without having to type "sudo -s" "iwconfig eth1 essid "TP-LINK" key **********" and sudo dhclient eth1 in kde every time i boot.

I really do appreciate the help

Joel

orionsune

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Re: Can access internet but not network or router?
« Reply #3 on: March 06, 2008, 10:32:50 pm »
disable the dhcp server startup script in /etc/init.d
thats all I had to do, then connected eth0 to my network, only problem was I had to manually create my windows shares because it didn't seem the network share discovery script was looking on my external nic for shares...
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colinjones

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Re: Can access internet but not network or router?
« Reply #4 on: March 06, 2008, 11:00:49 pm »
I'm not sure I understand what is connected to what here! But, either way, you don't need to disable the LMCE DHCP server to allow another DHCP server on your external network to work - it only services your internal network anyway. Couple of questions -

1 - have you got 2 physical networks (internal and external in the LMCE terminology) each connected to a different NIC on the LMCE core?
2 - when you say "router" can you distinguish them so we understand which one? So ADSL router/modem; wireless router/access point; LMCE router? Also, I note that wireless access points are usually just switches unless they have a broadband function as well and that makes a big difference to how you set up the network... so it is important only to call something a router if it actually is one otherwise it will confuse matters.
3 - you say that your core's external interface is connected to your wireless router... what then is the wireless router attached to? The ADSL modem? Its sounding more and more like your wireless device is actually a switch.... but I am having difficulty visualising the setup given the description....

orionsune

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Re: Can access internet but not network or router?
« Reply #5 on: March 07, 2008, 12:35:21 am »
maybe I should ellaborate on my suggestion.

remove the extra nic, you'll then have a eth0 and an eth0:0... by default, eth0:0 will have your internal gateway address, and the dhcp server will provide an ip to eth0 and any other device connected to the network through your eth0 card.   I don't know if this behavior is intentional or a bug, or a fluke on just my machines, but every single nic box i've built tries to use it's on dhcp server for getting ip instead of my existing router.

with only 1 nic, disable the dhcp server and either set your eth0 ip address manually, or allow your already existing dhcp server to assign one.  i'd go with setting it statically since a lmce box isn't really something that doesn't get moved around...
« Last Edit: March 07, 2008, 12:43:52 am by orionsune »
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colinjones

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Re: Can access internet but not network or router?
« Reply #6 on: March 07, 2008, 02:59:29 am »
Actually, I think it is just the nature of DHCP and subinterfaces - DHCP uses an Ethernet broadcast, which will be visible on both the main interface and subinterface. So even though the DHCP server is supposed to be serving the internal network only, the DHCP request from the external interface will still make it there, and so screw up your network connectivity if you are using different subnets for "internal" and "external".... it also means that you will see the strange behaviour of the DHCP-PnP system "discovering" itself as a fileserver, and ask you if you want to add it! It appears as DCEROUTER of course and can be a bit confusing. You should definitely so no, and don't ask again to this...

If the external and internal subnets are the same, you have one NIC, and you configure the LMCE DHCP server so that the gateway is your "real" router (say, the broadband router) as opposed to itself. Then turn off all other DHCP servers other than the LMCE one, you should have a network that works, doesn't push all the external traffic through the core, lets you add wireless APs, but LMCE's PnP system will still work. You won't have QoS for your telephony, and it may cause obscure problems because LMCE doesn't understand its own topology... but it should work OK. But definitely no VLANs...

orionsune

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Re: Can access internet but not network or router?
« Reply #7 on: March 07, 2008, 08:57:20 pm »
Quote
Actually, I think it is just the nature of DHCP and subinterfaces - DHCP uses an Ethernet broadcast, which will be visible on both the main interface and subinterface. So even though the DHCP server is supposed to be serving the internal network only, the DHCP request from the external interface will still make it there, and so screw up your network connectivity if you are using different subnets for "internal" and "external".... it also means that you will see the strange behaviour of the DHCP-PnP system "discovering" itself as a fileserver, and ask you if you want to add it! It appears as DCEROUTER of course and can be a bit confusing. You should definitely so no, and don't ask again to this...
that is what i figured.

Quote
If the external and internal subnets are the same, you have one NIC, and you configure the LMCE DHCP server so that the gateway is your "real" router (say, the broadband router) as opposed to itself. Then turn off all other DHCP servers other than the LMCE one, you should have a network that works, doesn't push all the external traffic through the core, lets you add wireless APs, but LMCE's PnP system will still work. You won't have QoS for your telephony, and it may cause obscure problems because LMCE doesn't understand its own topology... but it should work OK. But definitely no VLANs...
I think it's personal preference, but i'd rather use the DHCP server on my existing router/firewall/linuxbox/whatever if it's been proving to work reliably and remain stable.  Splitting your dependencies for internet connectivity should be a very HUGE no no.  I would disable the lmce dhcp server.  If not, then something happens to your lmce box, it's off, it's got a broken install, whatever, now your stuck taking extra steps to manually assign ip's to the other computers on your network to get internet connectivity while you repair your lmce box.  That is just one scenario of splitting your gateways responsibilities up.

I will admit i'm not too sure if disabling lmce's dhcp server will break it's device management, like for net shares, and definately no booting MD's without modifying your other DHCP server settings to point it in the right direction for it's boot kernel and filesystem. So I see it as a toss up, if you don't plan on use MD's then i'd disable the lmce dhcp.

We use vlans in our datacenters, and can understand why they are needed in an enterprise environment, hell i maintain our switches, but why would home users want to use vlans?  other than they have too much money and time and just feel like buying expensive cisco switches that support vlans...

I mean, whatever on all counts really, it comes down to personal preference, collin and I have put all the relevant information you need to make a sound decision on your network config... have fun...

I will leave this thread with my setup.
_____    ___________     _____________________________     ___________
|Inet| - |Cablemodem| - |Firewall Box/Wifi/Router/Whatever| - |Computer 1|
-----     -------------     ---------------------------------     -------------
                                     ^Running DHCP server^                  | Computer 2|
                                       Configured to serve MDs                ----------------
                                                                                       |LinuxeMCE Box| < 1 Network card, DHCP disabled
                                                                                        ---------------

Like I said, doing it like that requires some extra configuration to get diskless booting media directors to work.  I might make a wiki entry on how to do this one day when I run out of lmce stuff to troubleshoot.
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colinjones

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Re: Can access internet but not network or router?
« Reply #8 on: March 08, 2008, 01:20:07 am »
The biggest no no of all is not using LMCE as your internal DHCP server ...period! Yes, it will completely disable your PnP, netboot and the device management system. LMCE uses this to understand what devices are available etc. Simple - don't do it! Once your system gets its knickers in a knot, you will never untangle them! Just accept it as the DHCP server - I have never read a post yet that describes a network configuration that requires it be disabled (read plenty that it was clear the person just didn't want to use it, and tried to workaround it ...) Don't assume it is just a vanilla DHCP server, it isn't it is an integral part of how LMCE works. May be working at the moment ... but you won't be happy in a few months time when you try to make a simple change or addition to your LMCE network and it all falls in a heap and you need to rebuild :)

orionsune

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Re: Can access internet but not network or router?
« Reply #9 on: March 08, 2008, 01:35:28 am »
lol ok
« Last Edit: March 08, 2008, 01:53:35 am by orionsune »
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tschak909

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Re: Can access internet but not network or router?
« Reply #10 on: March 08, 2008, 04:48:39 pm »
I disagree, but okay.. what do I know? I've only looked at every square inch of the code....

-Thom

orionsune

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Re: Can access internet but not network or router?
« Reply #11 on: March 18, 2008, 12:09:43 am »
Disagree with who TSCHAK?  Because I have 3 systems in different houses currently running with disabled DHCP servers and everything has been detected perfectly so far.  MD's work after some tinkering with my other DHCP server to point clients to the right server for the remote filesystems, etc...  I even have OpenVPN setup on all 3, and all 3 houses share each others media shares... even the remote shares at the other houses are automatically detected once I configured OpenVPN for encrypted tunnel method (not bridging) and adding the appropiate routes to each network gateway...

So, what deetection scripts rely on DHCP?  I have also looked through all the scripts, most detection happens through NetBIOS names, not the  DHCP server.  Are there other devices that depend on it?  Like i said, my MD's work fine after some tinkering with my other DHCP server.  Let's see, network shares all work and detected just fine without dhcp.  It never detected my IP camera with dhcp enabled, so I assume that is a manual setup only deal.  Am I missing any other kind of network related devices that are autodetected other than network shares and MDs?  Maybe those cisco phones, since i'm never going to mess with that, my wireless plan can beat any hardwired or voip plan i've seen so far so thats pointless unless i want to waste a bunch of money on an orbiter/phone hybrid device... seems like a waste...  All the automation stuff isn't network related.... I admit I have not gotten very far with all the equipment lmce supports.  the only stuff I plan on messing with, i've already got running so far.  network shares, ip camera with motion detection, openvpn, bluetooth phone orbiter, lighting control, and 1 MD. 


I seriously don't understand you guys... I mean, I come in here because I liked the product and wanted to contribute my troubleshooting skills.  For starters my file shares didn't work correctly out of the box, but you guys defend it as if there was something wrong with my setup.  It turned out to be a different in how the wizard asks for user/pass between UI1 and UI2/3... later to find out if you use !@#...etc symbols in the pass, lmce won't mount that either.  I had to resolve this issue with some guidance from the community, and after reviewing the huge post, it had nothing to do with my setup or hardware, it was the unreliable nature of the detection scripts and device wizards.

Then myth would lock up, and from what I understand this was a big problem among alot of users.  It happen to be the way mythtv was called from the MythTV_Player plugin, I had to modify and recompile the code, and it was accepted as an official fix and applied to the code.

Do I need to write the guide now, so you guys can see how it's done?  It's nothing special, with only 1 network card, you give both eth0 and eth0:0 different IP addresses but in the same subnet, for example 192.168.0.100 for eth0 and 192.168.0.101 for eth0:0, then disable dhcp server and everything works perfectly. 

But i've got people telling me it's not possible?

You guys are kind of hostile when it comes to what you "think" is right... the word of the day should be "open-minded" and not "i'm right all the time because i've got green stars on my name"....

tschak, I found this comment you made in another post...
Quote
(b) use the Single NIC configuration defined in the wiki. However, if you turn off DHCP, you lose network plug and play, and will have to define all of your network resources in the Web Admin manually.

Except this was a response to another person posts saying this
Quote
3.  All my media is stored on a network file server.  I have read on the forums here that this is supported out of the box.  I wish this was correct.  In order to even get the MC to even detect the file server, I had to disable the DHCP server and Firewall (already have one, at a loss as to why there is one installed by default).  Now the MC detects the server and the shares,

Did you miss the part where he said he disabled his DHCP server and then it was detected?  His share still didn't work, but he says it picked it up.

and in the same post, he repeated

Quote
Once I disable the DHCP Server and the Firewall the system, the system stops trying to act as a router and automatically detects the file server and all of the network shares
reference: http://forum.linuxmce.org/index.php?topic=3429.0
You guys crack me up, i'm searching through other threads as i'm writing this, and I see soooooo many people talking about how lmce HAS to have dhcp running to detect anything, and it HAS to be setup as it was intended.... this is total bullshit... have any of you guys even tried? wow this is ridiculus, I can't believe so many of the contributing devs believe this, is there something i'm missing?  I mean seriously... i'm sitting here, watching my shit work perfectly fine without dhcp ont he lmce box.  If I am wrong, then please explain/elaborate because i'd love to know why i have 3 boxes and 2 virtual machines detecting shit just fine without a dhcp server running.

Look, I have 3 production lmce box's, and 2 boxes in a vmware machine, and all 5 of these has dhcp disabled and all 5 of them also detect all my network shares AND configures them perfectly.

Here is another set of quotations from a thread where I solved the guys problem for him.  He started off saying

Quote
How do I open the external interface on the core for file sharing?

My core is on our internal network.  I have the external interface obtaining an address from our router and the internal interface connected to an independant switch that all the MD's are connected to.

I advised him to disable his firewall and he responds with

Quote
Works beautifully, thanks.

now in retrospect, he says his automatic detection of network shares on his external interface works beautifully now... well his externel interface certainly isn't serving DHCP address, so why did his network shares get detected?  simple, because it used Netbios names not the DHCP server to find shares.
reference: http://forum.linuxmce.org/index.php?topic=4636.0

here is a thread where they discussed disabling dhcp, and never showed back up to report problems...

Quote
Go to the webadmin page, then go to Advanced > Network > Network Settings. From there you can unselect the DHCP server and save the page to finish the job. Had the same problem, the installer seemed to ignore my request that it not be a dhcp server.
reference: http://forum.linuxmce.org/index.php?topic=1298.0

here is another
Quote
I just didnt understand why MCE is trying to setup 2 IPs with one card, especially since I turned off DHCP server on the MCE machine.

I think im good though.
this thread also discussed disabling dhcp, and they appeared to be satisfied also.
reference: http://forum.linuxmce.org/index.php?topic=2080.0


Then I found this in /usr/pluto/bin the file Dhcpd-Plugin.sh and in that file I see
Code: [Select]
/usr/bin/tail -F /var/log/syslog | grep --line-buffered 'dhcpd: ' | bash -x /usr/pluto/bin/Dhcpd-Plugin-Parser.sh
So I understand how dhcp is SUPPOSED to help the pnp functions... by calling dhcpd-plugin-parses.sh when it sees a new dhcpd request from the syslog.  So to make sure i'm not making myself look like a fool here, I deleted all my network shares (by the way, to get them fully deleted so they'll be detected again and not ignored, I have to manually use somthing like phpmyadmin to delete the shares/fileservers ip address from plut_main -> pnpqueue table.) enabled my dhcp server, and watching /var/log/pluto/dhcp_pnp.log, this file remained empty as I was adding my automatically deteced network share... so with my next fileserver I watched the syslog for dhcpd entries just like the script is, when I saw a dhcpd entry for my second fileserver that booted up, I checked the /var/log/pluto/dhcp_pnp.log and again still empty, so I watched top, and never even saw the script being called... is this an old feature or something?  Maybe this is just to help determine if a device is online or not?  Or is it used for detecting other kinds of network devices like I mentioned earlier.

For the normal user who will probably only want to use the TVTuner, Remote Network Shares, this configuration of mine will work perfectly.  Beyond that, as I said to start with, i'm not sure.  But the basics... network share detection, works great.  In fact, after reviewing /usr/pluto/bin/StorageDevices_SambaRadar.sh and /usr/plut/bin/StorageDevices_Radar.sh reveal no depencies on the dhcp server... and in fact, it's using netbios names, and a for loop using the current subnet to ping ip's.  Not dhcp.

Besides, after research all this, I already see a very simple way to enable an external DHCP server AND retain lmce  pnp function as you guys claim.

If those scripts are operating the way I think, then using an NFS share exported from the machine where the DHCP server is running, with the dhcp configuration files, the lease file, and the syslog all residing on this exported share... then mount it under lmce, create symbolic links for the dhchp server config files and leases file... then point the script I mentioned to the nfsmountedshare/syslog instead of it's own....  eh.. just a wild stab in the dark...

back on subject... this is neither a rant or a rave, this is a plea for you guys to understand the most common function of network shares is NOT affected by the dhcp server... and I would honestly like to know what is, in case I run into this problem in the future with other network based devices.
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hari

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Re: Can access internet but not network or router?
« Reply #12 on: March 18, 2008, 12:52:07 am »
@orionsune:

I also ran lmce without dhcp for some weeks. When you search the forum I even came up with a solution to use arpwatch to feed the dhcp log parser.
Yes, if one is skilled as you, of course you can run lmce without dhcp. If you trigger device detection, create records on the other dhcp server and use things like next-server statements you will have a working system. But that setup is not for the newbie. They will wonder why the plugged in squeezebox don't work or why the cisco phone does not configure itself.

So I'm sure you understand why the general recommendation is to use LMCE as dhcp server. And its the only way to have this beast working as an appliance.

Now I use LMCE as dhcp server.. i have enough hazzle with IT at work.. so why make my life harder. LMCE handles that pretty good. And if you are that skilled it's easy to seperate networks and make a distinct vlan for lmce.

best regards,
Hari
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hari

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Re: Can access internet but not network or router?
« Reply #13 on: March 18, 2008, 12:52:50 am »
and thanks for that myth patch! Keep up the great work!
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orionsune

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Re: Can access internet but not network or router?
« Reply #14 on: March 18, 2008, 01:02:12 am »
Quote
@orionsune:

I also ran lmce without dhcp for some weeks. When you search the forum I even came up with a solution to use arpwatch to feed the dhcp log parser.
Yes, if one is skilled as you, of course you can run lmce without dhcp. If you trigger device detection, create records on the other dhcp server and use things like next-server statements you will have a working system. But that setup is not for the newbie. They will wonder why the plugged in squeezebox don't work or why the cisco phone does not configure itself.

So I'm sure you understand why the general recommendation is to use LMCE as dhcp server. And its the only way to have this beast working as an appliance.

Now I use LMCE as dhcp server.. i have enough hazzle with IT at work.. so why make my life harder. LMCE handles that pretty good. And if you are that skilled it's easy to seperate networks and make a distinct vlan for lmce.

best regards,
Hari
But hari, what i'm trying to say, is I have not done any of that.  The only modification I had to make, was my actual dhcp server setup to serve MD's and use LMCE box's filesystem instead of it's own.  I've made no other modification, and my shares were still detected fine.  I guess I was trying to say, for the normal user who will never get as far as using ip phones, and the sort... that this setup would suffice if they don't want to use it as a drop-in replacement of their current router.  Considering they'll probably never use devices that require the dhcp for detection.

I guess it comes down to whatever works and is easier for the user.  For me, tt was easier to disable dhcp and use lmce box as a client node, instead of a gateway.  My main reason for doing this is that i'm stubborn and don't like being told something isn't possible.  No just kidding, I did it because I spent alot of time and effort setting up my linux firewall for intrustion detection and alertting (i do network security irl), I didn't feel like trying to set all that up again under Ubuntu, because i'd have to learn a new flavor on top of the footwork (fingerwork, whichever you prefer) needed to set it up to begin with.  So it really was easier for me the way I did it.

Yes and I read your post about the arp method, and I was wondering why it was never implemented, I like it alot and believe it to be a GREAT choice for people in this situation.
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