Recap

I can ping all devices on the network except the gateway
(192.168.0.1) and in turn can not access outside of the network
without proxying through another device.

The system:

Lenovo x230 Tablet with a Realtek wifi adapter running on Quantal:

Network controller: Realtek Semiconductor Co., Ltd. RTL8188CE
802.11b/g/n WiFi Adapter (rev 01)

The wtf:

I can obtain an IP from the router


wlan0 Link encap:Ethernet HWaddr e0:06:e6:c2:d2:e0
inet addr:192.168.0.102 Bcast:192.168.0.255 Mask:255.255.255.0
inet6 addr: fe80::e206:e6ff:fec2:d2e0/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:178844 errors:0 dropped:0 overruns:0 frame:0
TX packets:101517 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:121465876 (121.4 MB) TX bytes:10612848 (10.6 MB)


I can ping other devices:


➜ ~ ping 192.168.0.101
PING 192.168.0.101 (192.168.0.101) 56(84) bytes of data.
64 bytes from 192.168.0.101: icmp_req=1 ttl=64 time=3.84 ms
64 bytes from 192.168.0.101: icmp_req=2 ttl=64 time=1.32 ms


I can not ping the gateway:


➜ ~ ping 192.168.0.1
PING 192.168.0.1 (192.168.0.1) 56(84) bytes of data.
From 192.168.0.102 icmp_seq=1 Destination Host Unreachable
From 192.168.0.102 icmp_seq=2 Destination Host Unreachable


My resolv.conf is autogenerated with:

“`
➜ ~ cat /etc/resolv.conf

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 127.0.1.1
search nc.rr.com
“`

My /etc/hosts:


➜ ~ cat /etc/hosts
127.0.0.1 localhost
127.0.1.1 quantal


My routing table:


➜ ~ route
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
default 192.168.0.1 0.0.0.0 UG 0 0 0 wlan0
link-local * 255.255.0.0 U 1000 0 0 wlan0
192.168.0.0 * 255.255.255.0 U 9 0 0 wlan0


Lastly, my module info for device:


➜ ~ modinfo rtl8192ce
filename: /lib/modules/3.5.0-17-generic/kernel/drivers/net/wireless/rtlwifi/rtl8192ce/rtl8192ce.ko
firmware: rtlwifi/rtl8192cfw.bin
description: Realtek 8192C/8188C 802.11n PCI wireless
license: GPL
author: Larry Finger
author: Realtek WlanFAE
author: lizhaoming
srcversion: DD4F3D83A75531AC98862F2
alias: pci:v000010ECd00008176sv*sd*bc*sc*i*
alias: pci:v000010ECd00008177sv*sd*bc*sc*i*
alias: pci:v000010ECd00008178sv*sd*bc*sc*i*
alias: pci:v000010ECd00008191sv*sd*bc*sc*i*
depends: rtlwifi,mac80211
vermagic: 3.5.0-17-generic SMP mod_unload modversions
parm: swlps:bool
parm: swenc:using hardware crypto (default 0 [hardware])
(bool)
parm: ips:using no link power save (default 1 is open)
(bool)
parm: fwlps:using linked fw control power save (default 1 is open)
(bool)


Things I’ve attempted:

Turning off fwlps, ips. Attempted to compile a driver from upstream
and even tried the latest daily mainline kernel for Quantal.

Has anyone seen this before? What really baffles me is that I can not
ping the gateway. To verify I can ping the gateway from another
system:


λ ~ → ping 192.168.0.1
PING 192.168.0.1 (192.168.0.1) 56(84) bytes of data.
64 bytes from 192.168.0.1: icmp_req=1 ttl=64 time=1.35 ms
64 bytes from 192.168.0.1: icmp_req=2 ttl=64 time=1.22 ms
64 bytes from 192.168.0.1: icmp_req=3 ttl=64 time=5.11 ms


This also doesn’t happen outside of my network as I was able to use
this laptop at UDS-R which kind of points to a router issue but
anything without a Realtek adapter works :

Solution

Turns out that this particular laptop was having issues resolving dns queries because on my particular cable modem/router there was an option for “Enable DNS relay” that was not checked (off). Once I checked that option my laptop suddenly started working! I tried to do some more research on what could be a possible reason as to why this specific laptop/wifi combo requires dns relay to be enabled on the router in order to access anything outside my network? Another odd thing is that if I directly connect the laptop to the router everything works so I assume it is something to do with the actual wifi driver/hardware. Anyway, I’m finally back to being able to use my recently purchased laptop 🙂

p.s – Im in London next …read more
Source: FULL ARTICLE at Planet Ubuntu