Author Topic: "No internet connection" 12.04 installer (solved)  (Read 456 times)

jamo

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"No internet connection" 12.04 installer (solved)
« on: February 21, 2014, 07:43:28 am »
Hopefully not premature, but if anyone else hits this gotcha, here's how I fixed it.

The problem: Right in the beginning of the installer, just after language selection, the installer checks requirements and reports on two things- The disk space (8.6Gb required) and the internet connection.

When the screen comes up, my internet connectinons is initially ticked (ie passes the test) and then it turns to a no-entry sign - ie fails the test and then the option to download updates while installing is also disabled.

I traced and resolved the problem as follows:
- "quitting" the installation which took me to an Ubuntu live desktop session
- opened a terminal to check network
- ping worked but no dns -> ie ping www.google.com failed but pinging the IP for www.google.com passed.
- modified /etc/resolv.conf: deleted the existing nameservers and replaced with the address of my local modem-router (192.168.10.1) which, I presume, forwards DNS requests to my ISP's nameservers.
- thereafter I was able to ping www.google.com successfully.
- Then re-ran the LinuxMCE12.04 installation from the desktop icon

This time, when I got to requirements, internet connection stayed clicked and I was able to proceed with installation.

I traced the problem to DNS. For some reason the nameservers specified in /etc/resolv.conf do not work for me so I just replaced them with a pointer to my local adsl-modem-router address (192.168.10.1) and that fixed it.

pigdog

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Re: "No internet connection" 12.04 installer (solved)
« Reply #1 on: February 21, 2014, 03:27:36 pm »
Hi,

Nice.

All I did was let it proceed and then in webadmin I'd swap interfaces and everything would work.

Cheers.

phenigma

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Re: "No internet connection" 12.04 installer (solved)
« Reply #2 on: February 22, 2014, 12:11:49 am »
Hopefully not premature, but if anyone else hits this gotcha, here's how I fixed it.

The problem: Right in the beginning of the installer, just after language selection, the installer checks requirements and reports on two things- The disk space (8.6Gb required) and the internet connection.

When the screen comes up, my internet connectinons is initially ticked (ie passes the test) and then it turns to a no-entry sign - ie fails the test and then the option to download updates while installing is also disabled.

I traced and resolved the problem as follows:
- "quitting" the installation which took me to an Ubuntu live desktop session
- opened a terminal to check network
- ping worked but no dns -> ie ping www.google.com failed but pinging the IP for www.google.com passed.
- modified /etc/resolv.conf: deleted the existing nameservers and replaced with the address of my local modem-router (192.168.10.1) which, I presume, forwards DNS requests to my ISP's nameservers.
- thereafter I was able to ping www.google.com successfully.
- Then re-ran the LinuxMCE12.04 installation from the desktop icon

This time, when I got to requirements, internet connection stayed clicked and I was able to proceed with installation.

I traced the problem to DNS. For some reason the nameservers specified in /etc/resolv.conf do not work for me so I just replaced them with a pointer to my local adsl-modem-router address (192.168.10.1) and that fixed it.

Jamo can you please paste the contents of resolv.conf as the dvd had it?  I have yet to sync the lastest snap.

J.

mkbrown69

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Re: "No internet connection" 12.04 installer (solved)
« Reply #3 on: February 22, 2014, 03:41:03 am »
Hi folks!

I've been looking into the DNS issues as well as the management of resolv.conf.  In 12.04, /etc/resolv.conf is now managed dynamically by the glibc resolver and resolvconf.  This is so that network mangler can dynamically manage Network configuration (and thus DNS lookups) on say a laptop that roams onto different Wi-Fi networks.  Historically, LMCE has been more like a server in trying to manage DNS settings statically, and now the two are conflicting to some extent.

I just finished working up a patch for Network_Setup.sh to add DNS settings into the /etc/network/interfaces file for the internal network, and when LMCE is running, the bind forwarders file handles outgoing DNS.  I haven't quite figured out exactly what to do about resolv.conf management, and at what stage to transfer the info obtained from Kubuntu's boot-up network config in resolv.conf over to the bind forwarders file.

Once set up properly, LMCE resolv.conf will look like this:
Code: [Select]
# Dynamic resolv.conf(5) file for glibc resolver(3) generated by resolvconf(8)
#     DO NOT EDIT THIS FILE BY HAND -- YOUR CHANGES WILL BE OVERWRITTEN
nameserver 127.0.0.1
search linuxmce.local

And the interfaces file will look like this:
Code: [Select]
# --- Internal NIC ---
iface eth1 inet static
        address 192.168.80.1
        netmask 255.255.255.0
        pre-up sysctl -q -e -w  net.ipv6.conf.eth1.disable_ipv6=0
        # DNS Settings for Internal Net
        dns-nameservers 192.168.80.1
        dns-search LinuxMCE.local

There won't be any DNS info in the external NIC (unless I add code for it; the challenge is again when to transfer it). External DNS is handled by the servers listed in /etc/bind/named.conf.forwarders, which is also setup in Network_Bind.sh, which is called from Network_Setup.sh. 

To make it interesting, the following scripts all backup or touch resolv.conf:
Code: [Select]
Network_DisplaySettings.sh:     local netExtDNS1=$(cat /etc/resolv.conf | grep "^nameserver" | head -1 | awk '{print $2}')
Network_DisplaySettings.sh:     local netExtDNS2=$(cat /etc/resolv.conf | grep "^nameserver" | tail -1 | awk '{print $2}')
Network_DNS.sh:if [ ! -e /etc/resolv.conf.pbackup ] ;then
Network_DNS.sh: cp /etc/resolv.conf /etc/resolv.conf.pbackup
Network_DNS.sh:if ! BlacklistConfFiles '/etc/resolv.conf' && ! BlacklistConfFiles '/etc/bind/named.conf.forwarders' ;then
Network_DNS.sh:$(grep nameserver /etc/resolv.conf | grep -v '#' | sed 's/nameserver//g; s/ *//g; s/^.*$/\t&;/')
Network_Parameters.sh:  if [ ! -e /etc/resolv.conf.pbackup ] ;then
Network_Parameters.sh:          cp /etc/resolv.conf /etc/resolv.conf.pbackup
Network_Parameters.sh:  if ! BlacklistConfFiles '/etc/resolv.conf' ;then
Network_Parameters.sh:          grep nameserver /etc/resolv.conf | grep -v '#' | sed 's/nameserver//g; s/ *//g' | tr '\n' ',' | sed 's/,$//'
Network_Setup.sh:# Empty resolv.conf files. Will be filled with static entries, or autofilled by dhcp
Network_Setup.sh:if [ ! -e /etc/resolv.conf.pbackup ] ;then
Network_Setup.sh:       cp /etc/resolv.conf /etc/resolv.conf.pbackup
Network_Setup.sh:: >/etc/resolv.conf
Network_Setup.sh:               if ! BlacklistConfFiles '/etc/resolv.conf' ;then
Network_Setup.sh:                               echo "nameserver $i" >>/etc/resolv.conf
Network_Setup.sh:               if ! BlacklistConfFiles '/etc/resolv.conf' ;then
Network_Setup.sh:                               echo "nameserver $i" >>/etc/resolv.conf

And the diskless setup scripts copy the core's resolv.conf to the moon directory, which won't work too well when the core is running properly, as resolv.conf will be set up to use localhost to hit bind on the same system. The diskless code will need a version of my patch to add the DNS settings to the interfaces file, or write the core's internal IP to resolv.conf.

I'll post my interface DNS patch into Trac shortly, so at least one issue gets addressed while we figure out the resolv.conf one.

EDIT:  added my patch to Jamo's ticket #2073.

Hope that helps!

/Mike
« Last Edit: February 22, 2014, 03:57:09 am by mkbrown69 »

jamo

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Re: "No internet connection" 12.04 installer (solved)
« Reply #4 on: February 22, 2014, 07:42:51 am »
Phenigma - you want what the original DVD (installer) put in resolve.conf? I'm afraid that's lost now to me as I have the new snap and  have installed.

Possy fixed that stuff and the new installer went through very smoothly on the core/hybrid.

MKBrown - sounds as if you have some idea there but please liase with possy before applying anything. The original problem that I noted above has definitely been resolved by his latest snapshot but there may still be some work to do. When I get a moment I'll read what you've written and try to understand it all.

pigdog

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Re: "No internet connection" 12.04 installer (solved)
« Reply #5 on: February 22, 2014, 02:43:48 pm »
Hi jamo,

Quote
as I have the new snap and  have installed

which snap are you running that sorts out the "Preparing to LinuxMCE" "is connected to the internet" check/not checked?

I'm chewing up my ISP download 'cap' max but I want to keep testing.

Cheers.

mkbrown69

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Re: "No internet connection" 12.04 installer (solved)
« Reply #6 on: February 22, 2014, 02:45:11 pm »
MKBrown - sounds as if you have some idea there but please liase with possy before applying anything. The original problem that I noted above has definitely been resolved by his latest snapshot but there may still be some work to do. When I get a moment I'll read what you've written and try to understand it all.
Jamo,

I don't have commit rights to SVN, and to be quite honest, I don't want commit rights.  I'll plug away fixing stuff I'm capable of, usually SysAdmin type stuff 'cause that's what I do, do up patches and stuff them into Trac.  Someone more knowledgable than I about LMCE internals can take 'em, leave 'em, tweak 'em, whatever.  I'll just do what I can do, and let others do what they're good at.

Hope that clarifies things!

/Mike

jamo

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Re: "No internet connection" 12.04 installer (solved)
« Reply #7 on: February 22, 2014, 07:05:38 pm »
pigdog - that would be snap LMCE-1204-20140221131028741.iso.

Have you used zsync to update "just the changes"? It is a lot quicker and uses a lot less of your cap.

Check this guide if you haven't
http://wiki.linuxmce.org/index.php/User:PlatypusPedersen#zsync_dowonload_for_Snapshots


Hi jamo,

which snap are you running that sorts out the "Preparing to LinuxMCE" "is connected to the internet" check/not checked?

I'm chewing up my ISP download 'cap' max but I want to keep testing.

Cheers.

jamo

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Re: "No internet connection" 12.04 installer (solved)
« Reply #8 on: February 22, 2014, 07:06:55 pm »
Jamo,

I don't have commit rights to SVN, and to be quite honest, I don't want commit rights.  I'll plug away fixing stuff I'm capable of, usually SysAdmin type stuff 'cause that's what I do, do up patches and stuff them into Trac.  Someone more knowledgable than I about LMCE internals can take 'em, leave 'em, tweak 'em, whatever.  I'll just do what I can do, and let others do what they're good at.

Hope that clarifies things!

/Mike

It does, thanks for the input and the info. I'm trying to learn at the same time so having some background sysadmin type detail posted helps me a lot.

phenigma

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Re: "No internet connection" 12.04 installer (solved)
« Reply #9 on: February 22, 2014, 07:14:13 pm »
Gentlemen.  There was a significant bug found last night in the firewall scripts that is likely causing all of these issues.  DNS is, and has been, working except during the initial stage of the DVD install, where it is *not* required.  If someone wants to help fix the issue we are very open to accepting patches.  I have applied 2 patches from mkbrown69 in the last few weeks (thanks mkbrown69!) and I will continue to do so.

Please wait for a new snapshot to be produced and do not use the current snapshot.  Thanks for testing guys!

J.