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reset default configuration sysctl.conf

+1 vote
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I have a problem with sysctl.conf, A week ago I have modified the file sysctl.conf for implementing security. Now, the machine is not reachable via ping

In IPtables configuration I have:

 -A INPUT -p icmp -s 111.111.111.111 -j ACCEPT (my home)
 -A INPUT -p icmp -s 222.222.222.222 -j ACCEPT (my office)

also commenting on all lines (#), the result does not change

at right time, I have commented all lines (#) in sysctl but result does not change in console, after the change, I gave:

 # sudo sysctl -p
posted Oct 6, 2013 by Mandeep Sehgal

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1 Answer

+1 vote

Set the following parameters in /etc/sysctl.conf (if this is related to sysctl.conf)

net.ipv4.icmp_echo_ignore_broadcasts = 0  
net.ipv4.icmp_echo_ignore_all = 0
answer Oct 6, 2013 by Anderson
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I have been using denyhosts for almost a year. To date I have only prevented one person logging in and that is ME ( I used the wrong login name).
Also, I know of no successful break-ins.

My iptables is as follows:

-P INPUT DROP
-P FORWARD DROP
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-N block
-A INPUT -j block
-A FORWARD -j block
-A block -i wifi_card -p tcp -m tcp --dport 12123 -j ACCEPT
-A block -i Nic_external -p tcp -m tcp --dport 12123 -j ACCEPT
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-A block -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT
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First, I think that the above will keep the bad guys out, Is that a true statement?

Sencondly, I have added a LOG rule just above the DROP rule and I have been monitoring it for about 1 1/2 weeks. As each entry is logged I have been adding it to /etc/hosts.deny. Currently there are 4318 ip adresses in the file and the number of packets that have been logged is 51592.

Denyhosts is for stopping ssh attempts and nothing else as I understand it.

Having over 4300 lines in /etc/hosts.deny causes almost no delay in logging in remotely.

Am I being to paranoid about keeping the bad guys out or is the iptable above completely adequate?

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