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New DHCP not working under WLAN
I recently unplugged my modem and router for the first time in a long time. I also recently updated to Ubuntu 11.04. I don't know which caused the problem, or if it was something else entirely.

What's happening now is that the laptop isn't picking up an address via DHCP. The modem is at 192.168.0.1. The router is at 192.168.2.1. The router is set up as a DHCP server, with the first address to give out set to 192.168.2.150.

For some reason the laptop keeps picking up 192.168.1.64. I've tried restarting networking, and ifdown/ifup on wlan0 and both report 'Ignoring unknown interface wlan0=wlan0'.

When anything else connects via wireless, we take turns kicking each other off. What did I break?
--

Drew
Expand Edited by drook July 31, 2011, 07:44:21 PM EDT
New Dunno. I usually punt and give fixed IP addresses.
New Re: DHCP not working under WLAN
what do you have in /etc/sysconfig/*pts/ifcfg-eth0
Any opinions expressed by me are mine alone, posted from my home computer, on my own time as a free American and do not reflect the opinions of any person or company that I have had professional relations with in the past 55 years. meep
New Don't have it
drook@tyler:~$ locate sysconfig

/usr/lib/python2.6/distutils/sysconfig.py
/usr/lib/python2.6/distutils/sysconfig.pyc
/usr/lib/python2.7/sysconfig.py
/usr/lib/python2.7/sysconfig.pyc
/usr/lib/python2.7/distutils/sysconfig.py
/usr/lib/python2.7/distutils/sysconfig.pyc
/usr/lib/syslinux/com32/include/klibc/sysconfig.h
--

Drew
New dang, thats redhat
search for eth0 (or wait for greg) there should be a text file that describes how the network card should be booted with parameters. Sounds like something isnt getting saved. Can you do a tcpdump -n -i eth0 in a command line while in another window renew the dhcp lease. The tcpdump will see what packets are being requested where and may have a clue
Any opinions expressed by me are mine alone, posted from my home computer, on my own time as a free American and do not reflect the opinions of any person or company that I have had professional relations with in the past 55 years. meep
New /etc/network/interfaces
That is Debian's config file. I'm assuming Ubuntu inherited it.
New NetworkManager can ignore that.
Ubuntu did inherit that file from Debian, but if NM is looking after networking, then anything you add to /etc/network/interfaces will get in it's way. The solution is to either disable NM (and all the dynamic work it does) or ignore that file and configure in the GUI.

Wade.

Static Scribblings http://staticsan.blogspot.com/
New Your Router is borked...
You have to re-fix your router's config.

Change the settings from "150 through 200" to "200 through 220" save it... reset it and then change it back.

Reason I say... the lapper is getting a "default" uPNP address and so is the other device. (Thank MS for pushing uPNP (which isn't "universal") and ZEROCONFIG (which isn't))

Either that or you've had your "network" stuff changed on you lapper.

Just use NetworkManager to setup your wireless and force it to make them "global" on your laptop.
New I'll give that a shot
Of course I'll be starting over when I dump the DSL for cable next month. Should probably get an "n" router to support the increased speed.
--

Drew
New Not quite uPNP
That would be the 169.254.1.0/16

Either the laptop has a static IP defined somehow, or something is sending out incorrect DHCP addresses.

My usual way out of this is to run Wireshark and trace the DHCP exchange. You would have to figure out which box has the offending MAC address.
New Getting DHCP from the wrong device
The modem offers 192.168.1.64 to all DHCP requests. It appears the router won't pick this address up. I've hard-coded the router to use that address -- per instructions here: http://zumaz.com/speedstream_5100B.html -- and when I connect a PC to the router it keeps getting that same address from the modem.
Aug  3 17:38:49 tyler dhclient: DHCPREQUEST of 192.168.2.101 on eth0 to 255.255.255.255 port 67

Aug 3 17:38:49 tyler dhclient: DHCPNAK from 192.168.0.1
Aug 3 17:38:49 tyler NetworkManager[466]: <info> (eth0): DHCPv4 state changed preinit -> expire
Aug 3 17:38:49 tyler dhclient: DHCPDISCOVER on eth0 to 255.255.255.255 port 67 interval 3
Aug 3 17:38:49 tyler dhclient: DHCPOFFER of 192.168.1.64 from 192.168.0.1

So the PC still knew it should be at .2.101 and requested it. But the modem responded NAK and gave out the same IP the router is using.

I don't have enough hair to pull out.

--

Drew
New Disable the DHCP server in the modem?
After all, that's the one stealing the requests.

I'm not surprised it's issuing an address that it should already know about. That's one of the older rules about setting up DHCP: don't manually set an address in it's pool.

Wade.
Static Scribblings http://staticsan.blogspot.com/
New Not available
This is a "simplified" firmware installed by the vendor. The choice is either use DHCP, and only issue the one address; or share the public IP assigned to the modem when it connects.


Hmmm ... I was really sure I wasn't set up that way, but that's the one thing I don't think I've tried switching. Off to try again ...
--

Drew
New Ouch. :-(
I'm glad I can buy and use whatever DSL modem I like with my ISP. Locked-down and/or "simplified" firmware sucks.

Perhaps the router used to be hiding the DHCP requests from the modem, as Scoenye suggested, and isn't anymore.

Wade.
Static Scribblings http://staticsan.blogspot.com/
New Some things not adding up
Your original post mentions the first address in the DHCP lease block is 192.168.2.150, but the PC is asking for .2.101. That is outside the block and may be the reason why the router is not responding.

Setting the router to .1.64 has no impact on the modem leasing out the address. It has no clue you assigned it to the router. (Some servers ping an address to be leased out of precaution, but not your modem apparently.)

The main thing is that the broadcast should not go through the router. In your case it does, so your "router" seems to be acting as a switch. If it is one of those 4+1 port thingies, are you sure you have the modem plugged in the "internet" port? If it really is a switch, then you'll have to make one of them stop acting as a DCHP server as the broadcasts will keep reaching both devices.

Lastly, what are the netmasks? Usually these devices use a 24 bit mask, but the modem seems to use at most a 23 bit mask. If it is even less, then the networks of the modem and router overlap which can lead to other problems. I usually switch one of the devices to a 172.16 network if they both are set for 192.168.x.x.
New There was a change in there
I originally had the router set up to start giving out DHCP at .2.150, but going with the Windows school of debugging -- when everything is set up right and it's still not working, start changing things that shouldn't matter and see what happens -- I changed it to start giving out at .2.100.

Then, with the router not plugged into the modem, the PC got .2.101 from the router. I plugged the router back into the modem and restarted networking on the PC and it grabbed .1.64.

I'll double-check what I have everything plugged into. Yes, it is a 4+1. If it turns out to be that, I'll be pissed at myself, but really grateful.
--

Drew
New Aaaaarrrrrrrrrgh! That got it
I had the modem plugged into the router's "uplink" port instead of its "WAN" port. Fixed that and now everything seems copacetic. Router is handing out IPs again, and they're in the right range.

Thanks for asking the dumb "did you plug it in right?" question.
--

Drew
New Glad you got it back. Dueling DHCP servers are always fun...

New Ummm...
Your router isn't being a router then.

Your router is acting as a "hub/switch" but not really since its trying to NAT, but then putting all the data WAN and LAN on the same network.

Only have ONE DHCP server per network and I think your modem is actually a Modem/firewall/router.

What model is the Modem and what is the Router?

Edit: AHA... it was acting as a switch/hub and putting the modem back in the WAN port... fixed it.
Expand Edited by folkert Aug. 4, 2011, 12:53:26 AM EDT
New Turns out the modem is a crippled router
The Speedstream 5100 is a router, but AT&T (formerly SBC/Yahoo!) put a custom firmware on it that disabled the router bits and locked the DHCP to a single address. (And user-written documentation confirms you can still access the router bits, but the next time you connect to AT&T with it they reset everything to default values.)

Funny thing was, when I had it plugged into the wrong port and checked the statistics readout on the modem I could see the multiple devices attached to it.
--

Drew
New AT&T just... gah...
AT&T is so far behind on infrastructure and trying to do workarounds to try and get decent throughput on it...

They are about $3B - $4B behind what they should be in infrastructure. They aren't adding aggregation links soon enough or often enough... This makes it an EVEN worse thing. as VLANs are then carried over alternate routes and causes huge lag to the first hop (the DSLAM Headend).

Yet in certain places they have BLAZING speeds, better than just about anyone. But in about 1% of the coverage areas they *do* cover. Anywhere else, they are horrible laggy and splotchy in throughput and response times.

The funny part is, they don't the money as to certain "acquisitions" being made by them, rather than invest in what really counts, they just want MORE customers...

I keep hearing in my head: If you build it, they will come.

If only AT&T understood that servicing current and existing customers, keeps turnover down a lot. But you know "Management and the Board" want larger and bigger.

Bleah.

I've got a couple of stories, I'd rather not put here. If you want them... you know how to get a hold of me.
New I can follow some of those TLAs,
but you have the whole plot in-head! Amazing (to us amateurs, especially.)

I'm assuming that your summary here Is backed by this overall grokking-to-fullness, as you rarely 'exaggerate' in these matters.
Even I can see that, 'If only AT&T understood that servicing current and existing customers, keeps turnover down a lot'.

Does it not appear then, that US Bizness (generally.. not always) follows-along the same illogic as the arrant Stupidity,
the ongoing sterility-of-imagination behind the TEAParty aims to ignore the effects of slashing [infrastructure repairs NOW, Etc.]
==all expenditures Blindly? This amidst a tottering, intractable depression-sans-jobs. Duh.

Is the rest of the planet That much smarter than our gaggle of ill-comprehending Suits?
HTF did 'we' get so iggerant-so-fast? It almost seems, today, as if a Willful aim (simply to dismantle the entire nexus of national survival?)
is the real agenda of some hate-filled minority--able to push their messages via all those Repo-$$ from Kochs, Roves and similar mindsets.
This makes no SENSE!!11ONE any way you parse the cause/effects which all can see. Nobody Wins!!

Must be Hell to be a savvy, logical ITer amidst such appalling absence-of-vision within the 'executive-class', way Above.
Can't fathom how a one works in such an environment daily, Knowing that management is running on 1/2-brain so consistently. How do YOU manage??

(I look at my crappy Comcast-crippled 'economy-speed', still at $500+ PER YEAR as the perfect comparo with Europe's attitude towards web-availability.
Here it's all about: what the $traffic$ will barely-bear; screw the overall effects. Screw any vision whatsoever. We be so Dumb, now.

Yeah.. it's ALL 'politics', in the end--even bizness IT-nonscience, if you're a standard Suit. Pity... really!
New Well, the place I work for...
Is not a Kool-Aid drinker and not a "Oh but its so easy and all you gotta do is this little thing." Place either. We are Honest and upstanding and really give good Triage for enhancement and anything else. (see (1))

Like making a WebSite all WSDL based... and then finding out you have to setup the WSDL service also. What? What do you mean your software doesn't do WSDL (mainly Windows only and slow as shit)

Oh now we have another customer that want an API that works with Lotus Notes... fine have notes use our RESTFUL services. What, you don't know what RESTFUL means?

I mean, I'm seeing "Marketing firms" speaking to customers and they paint pretty pictures... and all that, but... well... they are Bilking the customer of $50K/month and all they do is make pretty stuff in PhotoShop and Illustrator and then tell us to make it... Yet they were supposed to be the ones doing all the WebDesign...

No. Nobody want to hear the real grit... the truth... the hurt feelings... nothing. All they want is Rainbows and Unicorn farts.

GAH. Even people we thought weren't drinking the Kool-Aid... they are self lacing with even harsher amounts of the Kool-Aid Mix.

The Beast *IS* striking back. Harder than ever, just not out in broad daylight. Like they tried when they thought they had all the hands won.

Now they are doing stealth work. Under the guise of working together. Look at what Bill Gates $5B bought Education... NADA. they don't understand their own systems are dumbing people down. How can they, they are to close and directly affected by MORE.... MORE... MORE... We need a NEO to Fight Agent Gates and all his clones.

Someday... after all the fire is gone after the aftermath of this crap, we will look back and say: Damn glad that is over!

Then it starts all over again.

Yes, I'm ranting.

(1) We have a customer that has been burnt 3 times by SaaS/CRM providers. They have paid out the wazoo and gotten exactly no where.

They come to use and lay it on the line and say, we like your product, it just doesn't do {this feature set} we need to go forward. So we triage it and give them and estimate and payment plan with milestones, penalties for missing drop dead dates.

They lay it on the line again and say they are sick and tired of waiting for companies to do what they need done and hate waiting with very little effort and progress, but with paid money. They are used to waiting for the developers and companies and are usually calling and calling them for updates and progress.

We are the ones calling and calling them, we are moving to fast for them. We've missed two dates so far, but because they are dragging feet. They just aren't used to having to test and meeting and work with the vendors so quickly and often...

These people are pleased with our working ethic. I wish this was the norm.

We have plenty other customers that have Bricks for Employees and they stonewall and then blame us for failed/late stuff. When we get hauled out on the carpet, we have documentation that we communicated all the time and waited for answers, followed up every day or every tow days to once a week once it became apparent nothing was going to happen.

Its just not fair to be able to see these things with Vision. And to have to go down into the FOG and fumble our way around in the normality. GEEEZ!
New Lucky.. lucky to work Kool-Aid free,
especially in this Era of Hype. Neither you (I suspect) nor I (I Know) could function long in that world where neophyte hires put on their 'business card' such drivel as, "Working for Excellence" -- kinda like the guy who says , "Look: I'm Honest" cha cha. That's our !=brave new world of promising stuff you couldn't even imagine a workable path-to, but you have no qualms about promising it anyway.

I learned enough, just battling from 0-comprehension of that shiny new PDP-8, on through the basics (but not Basic) far enough to see, then: a glimpse of the manifold talents (and dedication) required to grok what "IT" was about (before it had that name.) Fortunately (I can say now) I was not attracted to that level of intricacy of puzzle-solving ... sufficiently to Go There.

Nor can I imagine how it could (next?) become true: that current 'Managers' who lack comprehension of the very-basics + some actual experience of crafting complex things, with discipline and tenacity: could "add-on" that underpinning, after-the-fact. ie They shall continue to 'manage' that which they are incompetent to understand even moderately well.

To me such a prospect seems ~~ like Redmond trying to glue-on 'Security', having conceived their CP/M-derived cash cow with no conception of that word. We see how that has gone (trying to stay 'compatible' etc. etc.)

So what does a company do? 1) Retrain selected Suits, 2) train already competent people to manage? or 3) muddle through with no changes in the way their hierarchy 'just happened' / "grew like Topsy?"--because nobody would!/could?? "retrain"

You would know better than I the likely choice, but I can't resist guessing: Door #3.
That seems to be the New Murican Way. But you couldn't build an accelerator with that MO. I doubt Murican Bizness can reform Itself, after all the easy money made before: just faking comprehension and winging it.

Hope you always find places persuaded-Otherwise than our ugly norm.

'Course my guess also would be that your lore and realizations should be passed on; could that be a better/more important? task than Doing [??]
(But I don't know how you'd feel about teaching--only I think that there are far-too-few IT folk who'd know or care what 'an oscilloscope' can contribute to learning stuff about Basic Stuff.) So it seems to me that an engineering-trained person also IT-*competent* shouldn't so much be ... daily solving IT-problems (however efficiently) as:

Training-up badly-needed New Ones. Well, if there's any org far-sighted enough to create a place for you to germinate some seeds--that is. (And, of course I know nada re your attitude re 'teaching'!)


My 3 Banana Republic deflated-kopecks

     DHCP not working under WLAN - (drook) - (23)
         Dunno. I usually punt and give fixed IP addresses. -NT - (Another Scott)
         Re: DHCP not working under WLAN - (boxley) - (4)
             Don't have it - (drook) - (3)
                 dang, thats redhat - (boxley)
                 /etc/network/interfaces - (scoenye) - (1)
                     NetworkManager can ignore that. - (static)
         Your Router is borked... - (folkert) - (2)
             I'll give that a shot - (drook)
             Not quite uPNP - (scoenye)
         Getting DHCP from the wrong device - (drook) - (13)
             Disable the DHCP server in the modem? - (static) - (2)
                 Not available - (drook) - (1)
                     Ouch. :-( - (static)
             Some things not adding up - (scoenye) - (3)
                 There was a change in there - (drook)
                 Aaaaarrrrrrrrrgh! That got it - (drook) - (1)
                     Glad you got it back. Dueling DHCP servers are always fun... - (scoenye)
             Ummm... - (folkert) - (5)
                 Turns out the modem is a crippled router - (drook) - (4)
                     AT&T just... gah... - (folkert) - (3)
                         I can follow some of those TLAs, - (Ashton) - (2)
                             Well, the place I work for... - (folkert) - (1)
                                 Lucky.. lucky to work Kool-Aid free, - (Ashton)

Ignore the man talking to his hand.
192 ms