oddball syslog entries ....

[Kurt Buff]

On Wed, Oct 8, 2014 at 12:22 AM, Arthur Chance <freebsd at qeng-ho.org> wrote:
> On 08/10/2014 04:01, William A. Mahaffey III wrote:
>> Over the last couple of days I am seeing some odd (to me) entries in my
>> messages file:
>>
>> Oct  7 15:03:24 kabini1 kernel: Limiting closed port RST response from
>> 324 to 200 packets/sec
>>
>> The stuff from Oct 2 is irrelevant, included for completeness/context.
>> The lines about 'Limiting closed port ....' are puzzling to me. Where
>> are they coming from ? Problem or chatter ? Enquiring minds wanna know
>> ;-) .... TIA for any clues ....
>>
>>
>
> I occasionally get this on a machine that sits squarely behind a locked down
> pfSense firewall. If you want to see what's causing it,
>
>         sysctl net.inet.tcp.log_in_vain=1
>
> (put into your /etc/sysctl.conf if you want it to last over reboots.) This
> will show you where the packet came from and which port on your machine was
> the target.
>
> In my case it seemed to be a mix of DNS responses from the outside world
> that arrived too late and a local long running Firefox occasionally pounding
> on the indent port (113) for no good reason I ever discovered.
>
> Nothing seems particularly dubious, unless the DNS responses were attempted
> spoofs, but my ISP is one of the better UK ones and I'd expect them to
> mitigate such attacks.


Outstanding - much simpler than what I proposed, and I learned
something new. Thanks for that.

Kurt