Posts Tagged ‘Fixing error: “net.ipv4.netfilter.ip_conntrack_tcp_timeout_syn_recv” is an unknown key’

Fixing error: “net.ipv4.netfilter.ip_conntrack_tcp_timeout_syn_recv” is an unknown key on Debian Linux

Tuesday, March 22nd, 2011

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If you’re trying to tune up your:

net.ipv4.netfilter.ip_conntrack_tcp_timeout_syn_recv = 30
net.ipv4.netfilter.ip_conntrack_tcp_timeout_time_wait = 30
net.ipv4.netfilter.ip_conntrack_tcp_timeout_fin_wait = 30
net.ipv4.netfilter.ip_conntrack_max = 1048576

in /etc/sysctl.conf and you come across the error messages;

"net.ipv4.netfilter.ip_conntrack_tcp_timeout_syn_recv" is an unknown key
"net.ipv4.netfilter.ip_conntrack_tcp_timeout_time_wait" is an unknown key
"net.ipv4.netfilter.ip_conntrack_tcp_timeout_fin_wait" is an unknown key
"net.ipv4.netfilter.ip_conntrack_max" is an unknown key

whether you’re executing:

debian:~# sysctl -p

in order to make the net.ipv4.netfilter.* values to be set as a kernel values to iptables, you need to modify your /etc/modules file and add the nf_conntrack_ftp in it, here is how:

echo 'nf_conntrack_ftp' >> /etc/modules

Now to make the new settings be reloaded issue the command:

debian:~# sysctl -p

Now the values will be properly set and you will see no longer the is an unknown key error messages like so:

net.ipv4.netfilter.ip_conntrack_tcp_timeout_syn_recv = 30
net.ipv4.netfilter.ip_conntrack_tcp_timeout_time_wait = 30
net.ipv4.netfilter.ip_conntrack_tcp_timeout_fin_wait = 30
net.ipv4.netfilter.ip_conntrack_max = 1048576