Here is the scenario.
I have an IP address 1.2.3.4 port 2000 sending udp packets to one unknown IP. I would like to find the unknown IP so I can block it with iptables.
Is there a way to do it with a script? Right now I am doing it manually by using
tshark -i eth1 -f "net 1.2.3.4 and src port 2000"
I'm not sure how to pipe this into a script and automatically find the destination ip.
I am trying to improve performance on my server. I have a few processes that need low jitter (less than 10ms variance).
I have a load average of 4 maximum on an i7-920 (4 physical cores, 8 with HT). There are about 10 processes ranging from 40% to 90% of a core user mode. System usage is 3% total. Total CPU usage is 80% max.
Will setting the kernel from 100hz to 1000hz improve the jitter if tickless and high resolution timers are already set?
This page seems to indicate it still does something. https://lkml.org/lkml/2009/4/28/401
How about changing from voluntary (PREEMPT_VOLUNTARY) to preemptible (PREEMPT)?
I have someone flooding me with random packets on random ports that are closed.
My server is responding to this with tcp-reset packets I think which is chewing up the outbound bandwidth too.
How do I use iptables to block tcp-reset packets?