Re: What on Centos is wiping out my eth0 IP address every 5minutes?

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> -----Original Message-----
> From: Rock
> Sent: Tuesday, July 23, 2013 17:46
> 
> QUESTION:
> Why does my Centos 6.4 laptop keep wiping out my eth0 IP address?

Googling
https://www.google.com/search?q=rhel+6+network+configuration&oq=rhel+6+network

https://access.redhat.com/site/documentation/en-US/Red_Hat_Enterprise_Linux/6/ht
ml/Deployment_Guide/ch-Network_Interfaces.html

> 
> SUMMARY:
> a) I set the IP address of eth0
> b) Everything works fine for 2 to 5 minutes
> c) Then, that eth0 IP address is (somehow?) wiped out I frustratingly 
> repeat that abc process (over and over and over again)

What is the contents of /etc/sysconfig/network-scripts/ifcfg-eth0 ?

> 
> BACKGROUND:
> My home network has been working perfectly and there is no problem 
> with my home network, nor my wlan0 WiFi access from my Centos laptop 
> to that home broadband network.
> 
> Inside the house, I never use the wired (eth0) NIC; but, I'm trying to 
> set up a wired/wireless connection outside the house and that is where 
> I'm running into this problem where Centos (automatically?) constantly 
> and repeatedly wipes out the IP address I set on eth0.
> 
> I can easily (constantly) change the IP address of the eth0 NIC back 
> to what I want it to be; but that IP address only stays set for about 
> 2 to 5 minutes; and then it wipes itself out (again & again).
> 
> Why? How do I stop this?
> (All I want is for eth0 to *stay* at the IP address I set it to!)
> 
> To give you more contextual detail, here's a typical sequence.
> 
> SIMPLE BASELINE:
>  Wireless NIC (wlan0) is turned off using a hardware switch on the  
> outside of the laptop (so that only one NIC is in play).
> 
> STARTING POINT: (eth0 has no IP address) $ ifconfig eth0 => eth0 Link 
> encap:Ethernet  HWaddr A0:BE:C1:D8:E5:F1
> =>   inet6 addr: fe80::f2de:f1ff:fe38:8591/64 Scope:Link 
> =>   UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
> =>   RX packets:3139 errors:0 dropped:0 overruns:0 frame:0
> =>   TX packets:3230 errors:0 dropped:0 overruns:0 carrier:0
> =>   collisions:0 txqueuelen:1000 
> =>   RX bytes:2403080 (2.2 MiB)  TX bytes:547895 (535.0 KiB)
> =>   Interrupt:20 Memory:f2600000-f2620000 
> 
> I EASILY CAN SET THE IP ADDRESS of eth0:
> $ sudo ifconfig eth0 192.168.1.100
> $ ifconfig eth0
> => eth0   Link encap:Ethernet  HWaddr A0:BE:C1:D8:E5:F1  
> =>        inet addr:192.168.1.100  Bcast:192.168.1.255  
> Mask:255.255.255.0
> =>        inet6 addr: fe80::f2de:f1ff:fe38:8591/64 Scope:Link
> =>        UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
> =>        etc.
> 
> At this point, I can now connect a wire from the RJ45 port of the 
> laptop, to the device (which happens to be a radio set to
> 192.168.1.20):
> 
> $ ping 192.168.1.20
> => PING 192.168.1.20 (192.168.1.20) 56(84) bytes of data.
> => 64 bytes from 192.168.1.20: icmp_seq=1 ttl=64 time=1.38 ms => 64 
> bytes from 192.168.1.20: icmp_seq=2 ttl=64 time=0.339 ms => 64 bytes 
> from 192.168.1.20: icmp_seq=3 ttl=64
> time=0.255 ms ^C => --- 192.168.1.20 ping statistics --- => 3 packets 
> transmitted, 3 received, 0% packet loss, time 2954ms => rtt 
> min/avg/max/mdev = 0.255/0.660/1.388/0.516 ms
> 
> I can even easily connect via port 80 (using Firefox on the
> laptop) to this device, e.g., $ firefox http://192.168.1.20
> 
> In fact, time and time (and time) again, everything works just fine, 
> for about 2 to 5 minutes, until, invariably, I lose all connectivity!
> 
> What seems to happen is that CentOS wipes out my IP address that I had 
> set for eth0. So, I lose all connectivity.
> 
> $ ifconfig eth0
> => eth0    Link encap:Ethernet  HWaddr A0:BE:C1:D8:E5:F1  
> =>         inet6 addr: fe80::f2de:f1ff:fe38:8591/64 Scope:Link
> =>         UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
> 
> I can repeat the process, and everything works again, for about 2 to
> 5 minutes. Then I lose my eth0 IP address again. 
> 
> WHAT I WANT:
> When I set eth0 to an IP address, I want eth0 to *stay* at that IP 
> address!
> 
> My question:
> Q: Why does setting an eth0 IP address only last about 5 minutes on 
> Centos?
> What am I doing wrong?
> What can I do to *keep* the IP address on eth0 that I set for eth0?
> 
> 
> _______________________________________________
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> CentOS@xxxxxxxxxx
> http://lists.centos.org/mailman/listinfo/centos
> 
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