Re: [EXTERNAL] VoIP Provider DDoSes

["Compton, Rich A" <Rich.Compton () charter com>]

Something you may want to consider is to put ACLs as far upstream as possible from your SBCs and only allow through 
what you need to the SBCs.  For example, apply a filter only permitting UDP 5060 and your RTP port range to your SBCs 
and then blocking everything else.  This is free and should stop a lot of common DDoS attacks before they ever get to 
your SBCs.  Even better if you can get your upstream ISP to apply the ACL.  DDoS attack traffic should be dropped as 
close to the source as possible.

-Rich

From: Mike Hammett <nanog () ics-il net>
Date: Tuesday, September 21, 2021 at 4:39 PM
To: "Compton, Rich A" <Rich.Compton () charter com>
Cc: NANOG list <nanog () nanog org>
Subject: Re: [EXTERNAL] VoIP Provider DDoSes

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links, or following guidance.
*nods* We have a Metaswitch SBC.

So as long as the pipe isn't full, an SBC is the buffer one needs? If the pipe is filled, pump it through {insert DDoS 
mitigation service here}?




-----
Mike Hammett
Intelligent Computing Solutions
http://www.ics-il.com

Midwest-IX
http://www.midwest-ix.com

________________________________
From: "Rich A Compton" <Rich.Compton () charter com>
To: "Mike Hammett" <nanog () ics-il net>, "NANOG" <nanog () nanog org>
Sent: Tuesday, September 21, 2021 4:59:06 PM
Subject: Re: [EXTERNAL] VoIP Provider DDoSes
Most of the larger DDoS mitigation appliances can block malformed SIP traffic and also can block volumetric/state 
exhaustion UDP floods.  A lot of VoIP companies have Session Border Controllers (SBCs) to protect public facing VoIP 
services.  SBCs are more application aware.  Kind of like a proxy based firewall just for VoIP.

-Rich

From: NANOG <nanog-bounces+rich.compton=charter.com () nanog org> on behalf of Mike Hammett <nanog () ics-il net>
Date: Tuesday, September 21, 2021 at 3:31 PM
To: NANOG list <nanog () nanog org>
Subject: [EXTERNAL] VoIP Provider DDoSes

CAUTION: The e-mail below is from an external source. Please exercise caution before opening attachments, clicking 
links, or following guidance.
As many may know, a particular VoIP supplier is suffering a DDoS. https://twitter.com/voipms

Are your garden variety DDoS mitigation platforms or services equipped to handle DDoSes of VoIP services? What nuances 
does one have to be cognizant of? A WAF doesn't mean much to SIP, IAX2, RTP, etc.



-----
Mike Hammett
Intelligent Computing Solutions
http://www.ics-il.com

Midwest-IX
http://www.midwest-ix.com
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