I am having an issue. Apparently we have times when we get a SYN flood perhaps or something and then get the following errors:
The most apparent one that over fills our Kernel log is the xt_hashlimit reached. When this happens the firewall begins to drop any new connections. Today it persisted for about 30 minutes and then auto resolved itself.
I'm still investigating whether this has to do with a SYN flood attack or something else.
Can anyone explain to me what the xt_hashlimit actually is? Is there any way of raising that 65536 # to something higher?
Code:
2013:01:27-12:18:13 asg1-1 kernel: [235864.124073] xt_hashlimit: max count of 65536 reached
2013:01:27-12:18:13 asg1-1 kernel: [235864.124151] xt_hashlimit: max count of 65536 reached
2013:01:27-12:18:13 asg1-1 kernel: [235864.124170] xt_hashlimit: max count of 65536 reached
2013:01:27-12:18:13 asg1-1 kernel: [235864.124280] xt_hashlimit: max count of 65536 reached
2013:01:27-12:18:18 asg1-1 kernel: [235869.128122] net_ratelimit: 218489 callbacks suppressed
2013:01:27-12:18:18 asg1-1 kernel: [235869.128126] xt_hashlimit: max count of 65536 reachedI'm still investigating whether this has to do with a SYN flood attack or something else.
Can anyone explain to me what the xt_hashlimit actually is? Is there any way of raising that 65536 # to something higher?