I had a perfectly functioning Ubuntu 12.04 system. I saw a YouTube video from DEFCON where a guy was discussing attacking home routers. In an Internet search of home router security I found a 2011 CERT paper on strengthening SOHO routers. One tip was to reduce the number of IPs on the LAN and to use static IPs.
I went into my 12.04 machine. I set up the static IP address, 192.168.1.7, that I had prepared at the router and lost Internet access. The LAN still works. When I boot to Windows 7, Windows 7 has Internet access. When I go back to DCHP in Ubuntu, reboot, and check I again have LAN access but no Internet access - different IP [192.168.1.11] from DHCP.
I completely reinstalled Ubuntu from a CD - same problem.
I did a search on askubuntu and found 2 previous posts
Wired Internet doesn't work on ubuntu 12.04 from April 29 internet access problem in 12.04 from April 28
I tried those things and they didn't work.
Any ideas, strategies, and tactics for troubleshooting this issue would be much appreciated.
Here are some diagnostics which may be helpful:
ifconfig eth0 eth0 Link encap:Ethernet HWaddr e0:cb:4e:b1:26:dc inet addr:192.168.1.11 Bcast:192.168.1.255 Mask:255.255.255.0 inet6 addr: fe80::e2cb:4eff:feb1:26dc/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:1816 errors:0 dropped:0 overruns:0 frame:0 TX packets:2168 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:162945 (162.9 KB) TX bytes:162147 (162.1 KB) Interrupt:49 route Kernel IP routing table Destination Gateway Genmask Flags Metric Ref Use Iface default 192.168.1.1 0.0.0.0 UG 0 0 0 eth0 link-local * 255.255.0.0 U 1000 0 0 eth0 192.168.1.0 * 255.255.255.0 U 1 0 0 eth0 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 127.0.0.1 search charter.net ping -c 4 18.104.22.168 PING 22.214.171.124 (126.96.36.199) 56(84) bytes of data. --- 188.8.131.52 ping statistics --- 4 packets transmitted, 0 received, 100% packet loss, time 3024ms The output of nm-tool: NetworkManager Tool State: connected (global) - Device: eth0 [Wired connection 1] ------------------------------------------- Type: Wired Driver: jme State: connected Default: yes HW Address: E0:CB:4E:B1:26:DC Capabilities: Carrier Detect: yes Speed: 1000 Mb/s Wired Properties Carrier: on IPv4 Settings: Address: 192.168.1.11 Prefix: 24 (255.255.255.0) Gateway: 192.168.1.1 DNS: 184.108.40.206 DNS: 220.127.116.11 DNS: 192.168.1.1
Results of ping -c 4 192.168.1.1 PING 192.168.1.1 (192.168.1.1) 56(84) bytes of data.
--- 192.168.1.1 ping statistics --- 4 packets transmitted, 0 received, 100% packet loss, time 3024ms
Note: This non-response by the router may be because I have set under Security | Firewall | Attack Check | Respond to Ping on Internet Ports [unchecked]. 192.168.1.1 brings up the router login screen on the laptop running Ubuntu 12.04.
I fixed it. Thank you for your assistance. I really appreciate your input on where to look as I tried to resolve this issue.
I went into the UP|Down arrow Icon on the menu bar. This brings up Network Connections. Under the Wired tab I picked Wired Connection 1 and choose [Edit]. That bring up a new options list with 4 tabs. I choose the 3rd Tab [IPv4 Settings].
Choices Method:Manual Addresses [Add] Address:192.168.1.7, Netmask:255.255.255.0 Gateway:192.168.1.1 DSN Servers: 18.104.22.168, 22.214.171.124, 192.168.1.1 Search Domains: charter.net DHCP Client ID: blank - no entry, no change Require IPv4 addressing for this connection to complete: unchecked - no entry, no change Routes - brings up a new options listing [Add] Address:192.168.1.7 Netmask:255.255.255.0 Gateway:192.168.1.1 - I left the 2 check box options blank and clicked OK. Back one screen "Available to all users" [checked] - no change, no entry Save Back one screen to Network Connections | Wired Close
Please excuse me if this fix explanation is too long or detailed. Having searched this resource for answers to questions in the past I know I appreciated when there was more detail. I am new to this forum and don't want to raise the ire of the Sys Admins, Power Users, and the like.