Getting hit hard by CHINANET

Ray Soucy rps at
Mon Mar 23 13:06:22 UTC 2015

I did a test on my personal server of filtering every IP network assigned
to China for a few months and over 90% of SSH attempts and other noise just
went away.  It was pretty remarkable.

Working for a public university I can't block China outright, but there are
times it has been tempting. :-)

The majority of DDOS attacks I see are sourced from addresses in the US,
though (likely spoofed).  Just saw a pretty large one last week which was
SSDP 1900 to UDP port 80, 50K+ unique host addresses involved.

On Wed, Mar 18, 2015 at 8:32 AM, Eric Rogers <ecrogers at>

> We are using Mikrotik for a BGP blackhole server that collects BOGONs
> from CYMRU and we also have our servers (web, email, etc.) use fail2ban
> to add a bad IP to the Mikrotik.  We then use BGP on all our core
> routers to null route those IPs.
> The ban-time is for a few days, and totally dynamic, so it isn't a
> permanent ban.  Seems to have cut down on the attempts considerably.
> Eric Rogers
> PDSConnect
> (317) 831-3000 x200
> -----Original Message-----
> From: NANOG [mailto:nanog-bounces at] On Behalf Of Roland Dobbins
> Sent: Wednesday, March 18, 2015 6:04 AM
> To: nanog at
> Subject: Re: Getting hit hard by CHINANET
> On 18 Mar 2015, at 17:00, Roland Dobbins wrote:
> > This is not an optimal approach, and most providers are unlikely to
> > engage in such behavior due to its potential negative impact (I'm
> > assuming you mean via S/RTBH and/or flowspec).
> Here's one counterexample:
> <
> Control.pdf>
> -----------------------------------
> Roland Dobbins <rdobbins at>

Ray Patrick Soucy
Network Engineer
University of Maine System

T: 207-561-3526
F: 207-561-3531

MaineREN, Maine's Research and Education Network

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