On Wed, Sep 13, 2017 at 9:59 AM, Krunal Shah <ks...@primustel.ca> wrote:
> It might be spoofed source IPs > > if you are seeing large fragmented udp packets.. it's almost always not spoofed. or historically speaking anyway it's not been spoofed. There are cases with dns reflection that include spoofing, but by the time you see the large packet .. that's not spoofed it's coming from the dns server talking to you, why it's talking to you is due to spoofing, but that's outside (most times) your span of control. > > Krunal Shah > > > > > > > -----Original Message----- > From: NANOG [mailto:nanog-boun...@nanog.org] On Behalf Of Mark Andrews > Sent: Tuesday, September 12, 2017 10:45 PM > To: Large Hadron Collider > Cc: nanog@nanog.org > Subject: Re: Protocol 17 floods from Vietnam & Mexico? > > > In message <08ed2903-c81c-aa2e-cd04-4fa117840...@gmx.com>, Large Hadron > Collider writes: > > Yes, I'm being UDP flooded. I worked that out by grepping /etc/protocols. > > > > > > On 12/09/2017 18:24, Matt Harris wrote: > > > Protocol 17 is UDP. UDP is pretty common on the internet. Not sure > > > why source and destination ports aren't being shown by your tool > > > there, might be malformed UDP packets designed to obscure themselves > > > from or otherwise evade some intrusion detection or firewall systems. > > No ports are listed because they are not the initial fragment of the UDP > packet. Only the initial fragment that contains the UDP header has the > ports reported. > > Mark > -- > Mark Andrews, ISC > 1 Seymour St., Dundas Valley, NSW 2117, Australia > PHONE: +61 2 9871 4742 INTERNET: ma...@isc.org > > > > -------------------------------- > This electronic message contains information from Primus Management ULC > ("PRIMUS") , which may be legally privileged and confidential. The > information is intended to be for the use of the individual(s) 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 message in > error, please notify us by telephone or e-mail (to the number or address > above) immediately. Any views, opinions or advice expressed in this > electronic message are not necessarily the views, opinions or advice of > PRIMUS. It is the responsibility of the recipient to ensure that any > attachments are virus free and PRIMUS bears no responsibility for any loss > or damage arising in any way from the use thereof.The term "PRIMUS" > includes its affiliates. > -------------------------------- > Pour la version en français de ce message, veuillez voir > http://www.primustel.ca/fr/legal/cs.htm > >
