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I am using CentOS-6.5 and configured static IP using NetworkManger(GUI). But this static IP will be often changing to DHCP IP automatically. This is happening since past couple of weeeks and still I couldn't find out the issue. I also tried below ipables rules block dhcp offer but no luck and still it is changing itself to DHCP but there is no any specific time for that(to get DHCP IP).
if I check the log(/var/log/messages) I found and entry related to dhcp as from 0.0.0.0.
So I am suspecting that anybody trying to gain access to my PC with such spoofed IPs or any daemon is changing to DHCP IP.
Expecting your kind help.
No, It did not help even after the static IP, service NetworkManager stop; chkconfig NetworkManager off. Also there is no DHCP reservation in the server side for my PC. So is there any other way that I can completely block dhcp request to my PC. Also request you to check the above mentioned IP Tables rules are correct to block dhcp IP.
Still I am facing the same problem, can anybody please suggest how can I completely block dhcp request. Because of this the many downloads(copying backup files using scp) from servers are terminating in the middle and then again I am deleting those incompleted scp files and restarting the downloads. I have already updated the packages using "yum update" command.
Excepting your kind help, I am using CentOS release 6.5 (Final) 64 bit O/S.
assuming you are using eth0 could you pls dump the contents of /etc/sysconfig/network-scripts/ifcfg-eth0?
Here is contents of that file.
# cat /etc/sysconfig/network-scripts/ifcfg-eth0
HWADDR=xx:yy:zz:12:34:56 # original mac has been removed.
Best to remove MAC add and anything sensitive.
Pls let me know what all the minimal entries are enough in this file.
And a copy of /sbin/ifconfig would be helpful. Again, remove all sensitive stuff.
I didn't understand that to where to copy this file and what to remove?
How do you know this is happening? I assume you expect to see the address 192.168.0.37 all the time?
I know this is happenning and that is why I came to here and expecting your help.
I execute "ifconfig" command, in that result my IP will be 192.168.0.245 or 192.168.0.253 or sometime someother IP. There is no any specific time for that to change into dhcp IP. Sometime my static IP will be fine for more than 2-3 days and sometime it will be changing everyday. So this is what I wanted to know whether anybody intentionally attacking to my PC. Now I have renamed below files also,
/sbin/dhclient to /sbin/dhclient.orig
/sbin/dhclient-script to /sbin/dhclient-script.orig