wireless can DHCP but not DNS?
summary: box ethernets via wire, but all wireless fails, including known-good providers: `ifconfig -a` shows a wireless IP#, but `nslookup` fails. How to fix or debug?
details:
I'm running LMDE UP8
https://en.wikipedia.org/wiki/Linux_Mint#Linux_Mint_Debian_Edition
http://blog.linuxmint.com/?p=2544
up-to-date on a new ThinkPad (new to me, anyway :-) with
$ inxi -Fxz
> System: Host: <filter> Kernel: 3.11-2-amd64 x86_64 (64 bit, gcc: 4.8.1)
> Desktop: Cinnamon 2.0.14 Distro: LinuxMint 1 debian
> ...
> Network: Card-1: Intel Centrino Advanced-N 6200 driver: iwlwifi ver: in-tree: bus-ID: 03:00.0
> IF: wlan0 state: down mac: <filter>
> Card-2: Intel 82577LM Gigabit Network Connection driver: e1000e ver: 2.3.2-k port: 1820 bus-ID: 00:19.0
> IF: eth0 state: up speed: 100 Mbps duplex: full mac: <filter>
I run wired ethernet at home and work, and installed debian on the newer laptop via wire without problems. I also have an older laptop with an older LMDE (UP5) which I won't be updating until I get everything working on the newer box :-( Wireless works as expected on the older laptop, including at the following locations:
* home (FreedomPop Hub Burst modem/router, security=WPA personal with encryption=AES)
* nearby municipal wireless (unsecured)
* work (security=WPA enterprise)
But at each of those locations, wireless fails on the newer laptop in the same way: I can DHCP (at least, I get an IP address) but not DNS ... which makes no sense to me! For example:
At home I can enable wireless on the modem/router, then startup the older box. It autoconnects to that SSID, and then
me@OldBox:~$ date ; nslookup www.google.com ; date
> Thu May 22 13:08:43 EDT 2014
> Server: 192.168.15.1
> Address: 192.168.15.1#53
...
me@OldBox:~$ date ; sudo ifconfig -a
> Thu May 22 13:08:45 EDT 2014
...
> wlan0 Link encap:Ethernet HWaddr <filter>
> inet addr:192.168.15.56 Bcast:192.168.15.255 Mask:255.255.255.0
> inet6 addr: <filter> Scope:Link
> UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
> RX packets:40217 errors:0 dropped:0 overruns:0 frame:0
> TX packets:32431 errors:0 dropped:0 overruns:0 carrier:0
> collisions:0 txqueuelen:1000
> RX bytes:15583645 (14.8 MiB) TX bytes:9273602 (8.8 MiB)
I can then browse to pages normally (using firefox). I then disable the old box's wireless (via NetworkManager), enable the new box's wireless, and connect ... or at least, NetworkManager gives connection notification. But when I do
me@NewBox ~ $ date ; nslookup www.google.com ; date
> Thu May 22 13:11:22 EDT 2014
> ;; connection timed out; no servers could be reached
> Thu May 22 13:11:37 EDT 2014
me@NewBox ~ $ date ; sudo ifconfig -a
> Thu May 22 12:53:07 EDT 2014
...
> wlan0 Link encap:Ethernet HWaddr <filter>
> inet addr:192.168.15.71 Bcast:192.168.15.255 Mask:255.255.255.0
> inet6 addr: <filter> Scope:Link
> UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
> RX packets:998 errors:0 dropped:0 overruns:0 frame:0
> TX packets:1099 errors:0 dropped:0 overruns:0 carrier:0
> collisions:0 txqueuelen:1000
> RX bytes:77446 (75.6 KiB) TX bytes:177995 (173.8 KiB)
FWIW, I have the same wireless experience at the other locations (open municipal wifi and secured wifi @ work): older box "just works," newer box connects and gets IP# but can't DNS (or browse).
Given that the older box (and in the latter cases, lots of other devices) works with these SSIDs, I suspect they are not misconfigured. Given that NetworkManager seems happy, and DHCP at least partly works, on the newer box, I suspect the newer box does not have a hardware problem. So I tend to suspect a software problem on the newer box. Am I missing something?
Mostly I'd like to know,
1. How to fix or debug the newer laptop?
2. How can the newer box get an IP# but no DNS server#s? I've used DHCP for many years but don't recall seeing this behavior before, except with misconfigured routers--which does not seem to apply in this case, because, in every instance, the old box works as expected.
Your assistance is appreciated, Tom Roche <Tom_Roche@pobox.com>
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