Linux Box booted up, but no networking. Frustrated......
First check the following tools:
bash-3.2# ls /sbin/arp
/sbin/arp
bash-3.2# ls /sbin/ifconfig
/sbin/ifconfig
bash-3.2# ls /sbin/route
/sbin/route
What's the output:
bash-3.2# ifconfig
lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.255.0.0
inet6 addr: ::1/128 Scope:Host
UP LOOPBACK RUNNING MTU:16436 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:0 (0.0 b) TX bytes:0 (0.0 b)
bash-3.2# arp -a
bash-3.2# route -n
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
bash-3.2#
Nothing useful...........; Try the following commands:
bash-3.2# ifconfig eth0 192.168.70.245 netmask 255.255.248.0 up
bash-3.2# route add default gw 192.168.64.1
bash-3.2# ifconfig
eth0 Link encap:Ethernet HWaddr 00:A0:C9:00:00:02
inet addr:192.168.70.245 Bcast:192.168.71.255 Mask:255.255.248.0
inet6 addr: fe80::2a0:c9ff:fe00:2/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:5 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:0 (0.0 b) TX bytes:390 (390.0 b)
lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.255.0.0
inet6 addr: ::1/128 Scope:Host
UP LOOPBACK RUNNING MTU:16436 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:0 (0.0 b) TX bytes:0 (0.0 b)
bash-3.2# ping 192.168.66.157
PING 192.168.66.157 (192.168.66.157) 56(84) bytes of data.
64 bytes from 192.168.66.157: icmp_seq=1 ttl=64 time=10.1 ms
64 bytes from 192.168.66.157: icmp_seq=2 ttl=64 time=0.292 ms
64 bytes from 192.168.66.157: icmp_seq=3 ttl=64 time=0.288 ms
64 bytes from 192.168.66.157: icmp_seq=4 ttl=64 time=0.287 ms
^C
--- 192.168.66.157 ping statistics ---
4 packets transmitted, 4 received, 0% packet loss, time 3008ms
rtt min/avg/max/mdev = 0.287/2.753/10.145/4.267 ms
bash-3.2# arp
Address HWtype HWaddress Flags Mask Iface
192.168.66.157 ether 00:0e:1e:0b:18:c0 C eth0
bash-3.2# route -n
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
192.168.64.0 0.0.0.0 255.255.248.0 U 0 0 0 eth0
0.0.0.0 192.168.64.1 0.0.0.0 UG 0 0 0 eth0
bash-3.2# ifconfig
eth0 Link encap:Ethernet HWaddr 00:A0:C9:00:00:02
inet addr:192.168.70.245 Bcast:192.168.71.255 Mask:255.255.248.0
inet6 addr: fe80::2a0:c9ff:fe00:2/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:1044 errors:0 dropped:0 overruns:0 frame:0
TX packets:11 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:141103 (137.7 KiB) TX bytes:866 (866.0 b)
lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.255.0.0
inet6 addr: ::1/128 Scope:Host
UP LOOPBACK RUNNING MTU:16436 Metric:1
RX packets:4 errors:0 dropped:0 overruns:0 frame:0
TX packets:4 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:344 (344.0 b) TX bytes:344 (344.0 b)
So packet is flowing now.
Commands for reference:
Showing posts with label Linux Networking. Show all posts
Showing posts with label Linux Networking. Show all posts
Friday, August 30, 2013
Linux Domain Name Lookup Command
For DNS concept, see the wiki link
# nslookup google.com
Server: 171.70.168.183
Address: 171.70.168.183#53
Non-authoritative answer:
Name: google.com
Address: 74.125.239.131
Name: google.com
Address: 74.125.239.132
Name: google.com
Address: 74.125.239.135
Name: google.com
Address: 74.125.239.142
Name: google.com
Address: 74.125.239.136
Name: google.com
Address: 74.125.239.129
Name: google.com
Address: 74.125.239.130
Name: google.com
Address: 74.125.239.134
Name: google.com
Address: 74.125.239.128
Name: google.com
Address: 74.125.239.137
Name: google.com
Address: 74.125.239.133
See wiki for an high level view.
http://en.wikipedia.org/wiki/Nslookup
; <<>> DiG 9.2.4 <<>> google.com
;; global options: printcmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 58279
;; flags: qr rd ra; QUERY: 1, ANSWER: 11, AUTHORITY: 4, ADDITIONAL: 4
;; QUESTION SECTION:
;google.com. IN A
;; ANSWER SECTION:
google.com. 172 IN A 74.125.239.142
google.com. 172 IN A 74.125.239.137
google.com. 172 IN A 74.125.239.133
google.com. 172 IN A 74.125.239.132
google.com. 172 IN A 74.125.239.130
google.com. 172 IN A 74.125.239.129
google.com. 172 IN A 74.125.239.135
google.com. 172 IN A 74.125.239.131
google.com. 172 IN A 74.125.239.134
google.com. 172 IN A 74.125.239.128
google.com. 172 IN A 74.125.239.136
;; AUTHORITY SECTION:
google.com. 96903 IN NS ns2.google.com.
google.com. 96903 IN NS ns1.google.com.
google.com. 96903 IN NS ns3.google.com.
google.com. 96903 IN NS ns4.google.com.
;; ADDITIONAL SECTION:
ns1.google.com. 271309 IN A 216.239.32.10
ns2.google.com. 239136 IN A 216.239.34.10
ns3.google.com. 274650 IN A 216.239.36.10
ns4.google.com. 273632 IN A 216.239.38.10
;; Query time: 5 msec
;; SERVER: 171.70.168.183#53(171.70.168.183)
;; WHEN: Fri Aug 30 12:56:23 2013
;; MSG SIZE rcvd: 340
# /usr/bin/host www.google.com
www.google.com has address 74.125.28.147
www.google.com has address 74.125.28.104
www.google.com has address 74.125.28.106
www.google.com has address 74.125.28.103
www.google.com has address 74.125.28.105
www.google.com has address 74.125.28.99
Here is one good article about those 3 tools.
http://blog.smalleycreative.com/linux/nslookup-is-dead-long-live-dig-and-host/
What happened if meeting the following issues:
bash-3.2# nslookup google.com
;; connection timed out; no servers could be reached
;; connection timed out; no servers could be reached
Check your configure file:
bash-3.2# cat /etc/resolv.conf
It is empty, so that is why :))
To solve the problem, do following configuration:
bash-3.2# cat /etc/resolv.conf
search comcast.com
nameserver 1.2.3.4
nameserver 4.3.2.1
search comcast.com
nameserver 1.2.3.4
nameserver 4.3.2.1
Monday, October 8, 2012
Linux Networking --- Bridge
When I am doing research on open virtual switch, which is different from Cisco's distributed Nexus 1000 virtual switch, found its command format is similar to original Linux bridge.
My Linux networking experience will start here. This is just the log for my own expertise upgrading experience. To start, I will dive in the following:
1.) Document: http://lxr.linux.no/#linux+v3.6.1/Documentation/networking/bridge.txt
2.) Source Code : http://lxr.linux.no/#linux+v3.6.1/net/bridge/
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