PlayStationNetwork blocking of CGNAT public addresses
tom.smyth at wirelessconnect.eu
Sun Sep 18 12:30:52 UTC 2016
as other responders have said it is an inherent issue with NAT in general,
on workaround is to limit the ratio of actual users to an external IPv4
address, the other thing we have seen from our Abuse contact emails from
PSN, is that malicious activity towards the PSN is often accompanied by
other malicious activities such as SSH brute force outbound and spaming...
I would suggest that
1) limit the ratio of users to an external ipv4 address as much as possible
(which would reduce the impact of one compromised customer bringing down
play time for other clients behind the same nat
2)do some "canary in the mine" monitoring for obviously malicious traffic
(loads of SMTP traffic outbound) and lots of connection requests to SSH
servers ... if you see that traffic from behind your CGNAT device .. just
temporarily block the internal ip of the user until they clean up their
this is the pain with NAT you have to do extra work in order prevent
infected users interrupting internet connectivity for other innocent
I think you can use simple firewall rules on your edge router to identify
multiple connections to SMTP and SSH in a short period of time..
If you do the minimum to detect that abuse then you cant be accused of
invading peoples privacy... (bear in mind obvious false positives)
(Monitoring systems etc) ...
Hope this helps,
On Fri, Sep 16, 2016 at 2:12 PM, Simon Lockhart <simon at slimey.org> wrote:
> We operate an access network with several hundred thousand users.
> we're putting the users behind CGNAT in order to continue to give them an
> service (we're all dual-stack, so they all get public IPv6 too). Due to the
> demographic of our users, many of them are gamers.
> We're hitting a problem with PlayStationNetwork 'randomly' blocking some
> of our
> CGNAT outside addresses, because they claim to have received anomalous, or
> 'attack' traffic from that IP. This obviously causes problems for the other
> legitimate users who end up behind the same public IPv4 address.
> Despite numerous attempts to engage with PSN, they are unwilling to give us
> any additional information which would allow us to identify the 'rogue'
> on our network, or to identify the 'unwanted' traffic so that we could
> block it, or use it to identify the rogue users ourselves.
> Has anyone else come up against the problem, and/or have any suggestions on
> how best to resolve it?
> Many thanks in advance,
Mobile: +353 87 6193172
PLEASE CONSIDER THE ENVIRONMENT BEFORE YOU PRINT THIS E-MAIL
This email contains information which may be confidential or privileged.
The information is intended solely for the use of the individual or entity
named above. If you are not the intended recipient, be aware that
any disclosure, copying, distribution or use of the contents of this
information is prohibited. If you have received this electronic
transmission in error, please notify me by telephone or by electronic mail
immediately. Any opinions expressed are those of the author, not the
company's .This email does not constitute either offer or acceptance of
any contractually binding agreement. Such offer or acceptance must be
writing. You are requested to carry out your own virus check before opening
any attachment. Thomas Smyth accepts no liability for any loss or damage
which may be caused by malicious software or attachments.
More information about the NANOG