I can connect to my house's wireless network just fine, but when I'm connected I can't browse the web. Firefox starts connecting to a site and then just poops out. This doesn't happen on my roommates' computers (running Windows) or on our 3DSes, so I know it's just my laptop.

I already tried

sudo dhclient -r 
sudo dhclient
sudo ifconfig eth0 down
sudo ifconfig eth0 up

Results of a few commands I was asked to run in comments:

ping -c 2 4.2.2.2
PING 4.2.2.2 (4.2.2.2) 56(84) bytes of data.
^C
--- 4.2.2.2 ping statistics ---
2 packets transmitted, 0 received, 100% packet loss, time 1007ms



ping -c 2 google.com
PING google.com (173.194.33.38) 56(84) bytes of data.

--- google.com ping statistics ---
2 packets transmitted, 0 received, 100% packet loss, time 1006ms



nm-tool

NetworkManager Tool

State: connected (global)

- Device: eth0 -----------------------------------------------------------------
  Type:              Wired
  Driver:            atl1c
  State:             unavailable
  Default:           no
  HW Address:        88:AE:1D:6B:4E:E7

  Capabilities:
    Carrier Detect:  yes
    Speed:           100 Mb/s

  Wired Properties
    Carrier:         off


- Device: wlan0  [JUSTICE] -----------------------------------------------------
  Type:              802.11 WiFi
  Driver:            ath9k
  State:             connected
  Default:           yes
  HW Address:        1C:65:9D:65:C6:31

  Capabilities:
    Speed:           1 Mb/s

  Wireless Properties
    WEP Encryption:  yes
    WPA Encryption:  yes
    WPA2 Encryption: yes

  Wireless Access Points (* = current AP)
    HOME-9B18:       Infra, 00:26:F3:53:9B:18, Freq 2412 MHz, Rate 54 Mb/s, Strength 34 WPA WPA2
    cougdad48 Network: Infra, 60:33:4B:E4:C4:5D, Freq 2437 MHz, Rate 54 Mb/s, Strength 22 WPA2
    cougdad48 Guest Network: Infra, 66:33:4B:E4:C4:5D, Freq 2437 MHz, Rate 54 Mb/s, Strength 20 WPA2
    belkin.ade:      Infra, 94:44:52:FF:8A:DE, Freq 2457 MHz, Rate 54 Mb/s, Strength 20 WPA WPA2
    *JUSTICE:        Infra, 00:24:01:7B:9F:7E, Freq 2462 MHz, Rate 54 Mb/s, Strength 88 WEP
    CenturyLink:     Infra, B2:B2:DC:8E:E2:58, Freq 2462 MHz, Rate 54 Mb/s, Strength 17 WPA WPA2

  IPv4 Settings:
    Address:         192.168.0.11
    Prefix:          24 (255.255.255.0)
    Gateway:         192.168.0.1

    DNS:             192.168.0.1

(JUSTICE is my home's network.)

  ping -c 2 198.168.0.1
  PING 198.168.0.1 (198.168.0.1) 56(84) bytes of data.

  --- 198.168.0.1 ping statistics ---
  2 packets transmitted, 0 received, 100% packet loss, time 1007ms