- Red Hat Enterprise Linux 5
- Red Hat Enterprise Linux 6
- Red Hat Enterprise Linux 7
what are the steps to change and modify the maximum allowed TCP sessions on the server.
/var/log/messagesstates that packets are being dropped due to the limit being reached.
It's possible to increase limit, but at a cost of more memory being used (how much per each connection would be possible to derive from looking at the structures used in the kernel code).
The current limit can be viewed in one of these files, the exact file can vary based on RHEL version.
- If the connections are legitimate the limit can be increased by echoing the number to the conntrack_max file as shown below:
cat 250000 >/proc/sys/net/netfilter/nf_conntrack_max
- To make the changes permanent edit the /etc/sysctl.conf file and edit or add a line based on the location of the
ip_conntrack_maxfile of the respective RHEL version.
net.netfilter.nf_conntrack_max = 250000
/var/log/messages shows that no of TCP connections has been exhausted and kernel is dropping packets.
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