RE: [MLUG] RTNETLINK answers: Network is unreachable -- SOLVED

["Cutts III, James H." <EMAIL:PROTECTED>]

Ladies and Gentlemen,

I would like to thank you for your kind support.  I have just resolved
two problems plaguing my office.  It turns out to be a "well, duh",
"can't see the forest for the trees" kind of problem. 

Since my production server was down, I was focusing on that problem.
The other problem in the office is the failure of one of the three
network jacks to work.  The network port wouldn't work because it's the
VLAN for the server and the server wouldn't work because it wasn't
plugged into the correct network port.  As a rule, I don't try to use a
non-functioning network port to get a non-functioning computer to work.


It was thanks to the combination of Bryan Venable's commentary on VLANs
and ports, and the arrival of the DoITs service man to look at the port,
that caused me to put everything together and move network connections.


I appreciate everyone's help and kind thoughts.

James H. Cutts III
CARES & CORI - 143C Mumford

P.S.  I've labeled the port now.
 

> -----Original Message-----
> From: EMAIL:PROTECTED 
> [mailto:EMAIL:PROTECTED] On Behalf Of Cutts 
> III, James H.
> Sent: Wednesday, April 11, 2007 1:01 PM
> To: MLUG Members
> Subject: RE: [MLUG] RTNETLINK answers: Network is unreachable
> 
> The "tcpdump" command gets "stuff" coming by on the screen.  
> It looks like a time stamp, protocols, addresses,...
> 
> I've run "iptraf" and I'm getting UDP packets on ports 138, 
> 137, 123, 68 and 67.
> 
> Last night I moved the machine to a new port and since then, 
> I've moved it back to the same port.  I guess it may be a 
> VLAN issue.  
> 
> I'll check with campus networking to see if this may resolve 
> my issues.
> 
> 
> Thanks for the suggestions and the explanations.
> 
> James H. Cutts III
> CARES & CORI - 143C Mumford
> 
>  
> 
> > -----Original Message-----
> > From: EMAIL:PROTECTED 
> > [mailto:EMAIL:PROTECTED] On Behalf Of 
> Bryan Venable
> > Sent: Wednesday, April 11, 2007 12:03 PM
> > To: MLUG Members
> > Subject: Re: [MLUG] RTNETLINK answers: Network is unreachable
> > 
> > When you connect to your original network port (not the
> > netgear) and run (as root):
> > 
> > tcpdump -i eth0 -n
> > 
> > What kind of traffic do you see? If you aren't getting 
> anything, but 
> > your NIC has link, then your port may have been blocked or removed 
> > from the VLAN.  It sounds like you don't manage the switch you are 
> > connecting to.  Have you contacted the network admin(s)?  If you 
> > changed which port you were connecting to, they may 
> purposefully have 
> > security mechanisms in place to prevent that change from "just 
> > working".
> > 
> > If you *do* see traffic, and you changed ports, then the 
> new port may 
> > simply be on a different VLAN, in which case you should see 
> broadcast 
> > traffic that will indicate what VLAN it is.  If that 
> happens you will 
> > need the network admin(s) to change the VLAN membership of 
> that port 
> > or you will need to change your server's IP, whichever is 
> simplest - 
> > I'd guess the VLAN change.
> > 
> > If you didn't change ports then there still could be 
> something going 
> > on at the switch.  In general, if you have link and your 
> interface and 
> > routing configurations are the same, the problem will be at the 
> > switch.  Unless it's been an exceptionally long time since 
> the server 
> > was rebooted, the chances that your configuration changed 
> unexpectedly 
> > are slim to none.
> > 
> > Good luck.
> > 
> > 
> > On 4/11/07, Cutts III, James H. <EMAIL:PROTECTED> wrote:
> > >
> > >
> > > Jason,
> > >
> > > The commands you suggested did not generate any error 
> messages, nor 
> > > did they solve the problem.
> > >
> > > I tried the netmask and gateway you suggested - it didn't 
> work.  :-(
> > >
> > > Then I tried the netmask and gateway in my ifcfg-eth0 - it
> > didn't work
> > > either.  :-(
> > >
> > > Michael Proctor asked about changing the changing NICs.  I
> > have heard
> > > of that happening.  I hadn't thought of that.  When I unplug the 
> > > network cable, the box protests that "e100: eth0 Link is
> > Down".  This
> > > makes me believe that I've got the right card and cable.
> > >
> > > I have borrowed a "simple" 4 port Netgear (wireless) 
> router.  If I 
> > > plug the box in to the router and ping something I see the
> > lights on
> > > the router blink.  Any suggestions of ways to use this
> > router to see
> > > what is actually getting shoved out of the box?
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > > James H. Cutts III
> > >
> > > CARES & CORI - 143C Mumford
> > >
> > >
> > >
> > >  ________________________________
> > >  From: EMAIL:PROTECTED 
> > > [mailto:EMAIL:PROTECTED] On Behalf Of
> > McIntosh Jason
> > > Sent: Wednesday, April 11, 2007 10:33 AM
> > > To: Members MLUG
> > >
> > > Subject: Re: [MLUG] RTNETLINK answers: Network is unreachable
> > >
> > >
> > > Hrmm, I re-read the original email.  If you try turning off the 
> > > interface (i.e. ifdown eth0) then try:
> > > ifconfig  eth0 128.206.25.130 netmask 255.255.255.0 up route add 
> > > default gw 128.206.25.254
> > >
> > >
> > > (I think that's the syntax off the top of my head) - see if
> > that gets
> > > you up and running.  if so, then it is an issue with your
> > network configuration.
> > > i.e. the syntax for the files in /etc/sysconfig/network/
> > have changed,
> > > or something along those lines.  ifup and ifdown merely are
> > shortcuts
> > > to execute the ifconfig command with the appropriate information 
> > > pulled from those files.
> > >
> > >
> > > Jason
> > >
> > >
> > >
> > > 
> /--------------------------------------|---------------------------\
> > > | Jason McIntosh                       | CELL: 
> 573-424-7612        |
> > > | Webmaster, thinker, programmer, etc. | WORK: 
> 573-884-3865        |
> > > | http://mcintosh.poetshome.com/blog/  |
> > >        |
> > > 
> |------------------------------------------------------------------|
> > > |"How should I know if it works?  That's what beta 
> testers are     |
> > > |for.  I only coded it."                                  
>          |
> > > |(Attributed to Linus Torvalds, somewhere in a posting)   
>          |
> > > 
> \--------------------------------------|---------------------------/
> > >
> > >
> > >
> > >
> > >
> > > On Apr 11, 2007, at 10:24 AM, McIntosh Jason wrote:
> > >
> > > They have changed, but that won't prevent a network 
> connection from 
> > > happening.  That's just for DNS resolution (i.e. how to convert 
> > > mlug.missouri.edu to 128.206.whatever).
> > > This issue sounds more like binding the driver to the
> > interface.  It
> > > is worth trying another network card though to see if it
> > might work better.
> > > Jason
> > >
> > >
> > >
> > > 
> /--------------------------------------|---------------------------\
> > > | Jason McIntosh                       | CELL: 
> 573-424-7612        |
> > > | Webmaster, thinker, programmer, etc. | WORK: 
> 573-884-3865        |
> > > | http://mcintosh.poetshome.com/blog/  |
> > >        |
> > > 
> |------------------------------------------------------------------|
> > > |"How should I know if it works?  That's what beta 
> testers are     |
> > > |for.  I only coded it."                                  
>          |
> > > |(Attributed to Linus Torvalds, somewhere in a posting)   
>          |
> > > 
> \--------------------------------------|---------------------------/
> > >
> > >
> > >
> > >
> > >
> > > On Apr 11, 2007, at 10:22 AM, George Robb wrote:
> > >
> > >
> > > Didn't the name servers change from 2.252 to  128.206.10.3
> > and 128.206.10.2?
> > >
> > >
> > > You may want to call the op's center 4-2182 and double check me.
> > >
> > >
> > > Worst case comment out the current nameserver entries and
> > manually add
> > > the new ones.
> > >
> > >
> > > A shot in the dark...  ;)
> > >
> > >
> > > George
> > >
> > >
> > >
> > >
> > > On Apr 11, 2007, at 10:04 AM, Cutts III, James H. wrote:
> > >
> > >
> > >
> > > Ah, debugging questions.  I can deal with them.
> > >
> > >
> > > Static IP: 128.206.25.130
> > >
> > >
> > > /etc/resolv.conf
> > > nameserver 128.206.2.252
> > > nameserver 128.206.2.242
> > > search missouri.edu
> > >
> > >
> > > Yes, I've checked the cables.
> > >
> > >
> > > The server is on a VLAN in the MU system.  Might there be 
> a problem 
> > > beyond my port?
> > >
> > >
> > > Thanks,
> > > James.
> > >
> > >
> > >
> > >
> > > -----Original Message-----
> > > From: EMAIL:PROTECTED 
> > > [mailto:EMAIL:PROTECTED] On Behalf Of 
> George Robb
> > > Sent: Wednesday, April 11, 2007 9:51 AM
> > > To: MLUG Members
> > > Subject: Re: [MLUG] RTNETLINK answers: Network is unreachable
> > >
> > >
> > > Are you static or dynamic for your IP?  What does your /etc/ 
> > > resolv.conf look like?  Double checked that your cable is good?
> > >
> > >
> > > ;)
> > >
> > >
> > > George
> > >
> > >
> > > On Apr 11, 2007, at 9:45 AM, Cutts III, James H. wrote:
> > >
> > >
> > >
> > > I needed to move my production server, Ronald, (running Red Hat 9
> > > (Shrike) 2.3.20-31.9) while reconfiguring the server room.  
> > The room
> > > is nicely rearranged and ready for the return of the computers.
> > >
> > >
> > > After issuing the "halt" command Ronald, issued a few 
> protest about 
> > > it's inability to umount /usr2 due to a file being too 
> large.  But 
> > > otherwise it went down nicely (I think).
> > >
> > >
> > > I've restarted the box and everything appears to be 
> running nicely - 
> > > except that it can't get to nor be seen by the internet 
> (nor campus 
> > > network for that matter).
> > >
> > >
> > > A "/sbin/ifup eth0" produces the responses:
> > > e100: eth0 NIC Link is Up 100 Mbps Half duplex RTNETLINK answers: 
> > > Network is unreachable RTNETLINK answers: Invalid argument
> > >
> > >
> > > I've been "visited" by my boss and received comments from 
> users that 
> > > the server is down.  Their comments haven't been helpful, 
> hopefully 
> > > MLUG members will be more constructive.
> > >
> > >
> > > Please!
> > >
> > >
> > > James H. Cutts III
> > > CARES & CORI
> > > MU
> > >
> > >
> > >
> > >
> > > _______________________________________________
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> > >
> > >
> > >
> > >
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> > >
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> > >
> > >
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