It could be a DNS amplification attack, with the source IP forged. They may be hoping you "reply" to the forged source with a response greater than the cost of them sending the query.
Of course you'd have to actually be running a poorly configured DNS server on that IP for this to work... On Fri, Apr 6, 2012 at 11:47 AM, Keegan Holley <keegan.hol...@sungard.com>wrote: > Have you tried contacting the owner of the IP? A DDOS attack from that > particular IP would be ironic. > > # > # The following results may also be obtained via: > # > > http://whois.arin.net/rest/nets;q=72.20.23.24?showDetails=true&showARIN=false&ext=netref2 > # > > Staminus Communications STAMINUS-COMMUNICATIONS (NET-72-20-0-0-1) 72.20.0.0 > - 72.20.63.255 > DDOSWIZ.COM STAMINUS-COMMUNICATIONS (NET-72-20-23-0-1) 72.20.23.0 - > 72.20.23.63 > > > # > # ARIN WHOIS data and services are subject to the Terms of Use > # available at: https://www.arin.net/whois_tou.html > # > > > > 2012/4/6 Nathan Eisenberg <nat...@atlasnetworks.us> > > > Anyone else seeing this sort of noise lately? > > > > 10:35:00.958556 IP 72.20.23.24.53 > 66.171.180.48.53: 952+ [1au] ANY? > > ripe.net. (38) > > 10:35:00.961055 IP 72.20.23.19.53 > 66.171.180.48.53: 952+ [1au] ANY? > > ripe.net. (38) > > 10:35:01.262461 IP 72.20.23.19.53 > 66.171.180.48.53: 952+ [1au] ANY? > > ripe.net. (38) > > 10:35:01.350979 IP 72.20.23.24.53 > 66.171.180.48.53: 952+ [1au] ANY? > > ripe.net. (38) > > 10:35:01.351001 IP 66.171.180.48 > 72.20.23.24: ICMP 66.171.180.48 udp > > port 53 unreachable, length 74 > > 10:35:01.573166 IP 72.20.23.19.53 > 66.171.180.48.53: 952+ [1au] ANY? > > ripe.net. (38) > > 10:35:01.573204 IP 66.171.180.48 > 72.20.23.19: ICMP 66.171.180.48 udp > > port 53 unreachable, length 74 > > 10:35:01.730128 IP 72.20.23.24.53 > 66.171.180.48.53: 952+ [1au] ANY? > > ripe.net. (38) > > 10:35:01.970730 IP 72.20.23.19.53 > 66.171.180.48.53: 952+ [1au] ANY? > > ripe.net. (38) > > 10:35:02.121218 IP 72.20.23.24.53 > 66.171.180.48.53: 952+ [1au] ANY? > > ripe.net. (38) > > 10:35:02.374853 IP 72.20.23.19.53 > 66.171.180.48.53: 952+ [1au] ANY? > > ripe.net. (38) > > 10:35:02.374879 IP 66.171.180.48 > 72.20.23.19: ICMP 66.171.180.48 udp > > port 53 unreachable, length 74 > > 10:35:02.493257 IP 72.20.23.24.53 > 66.171.180.48.53: 952+ [1au] ANY? > > ripe.net. (38) > > 10:35:02.493270 IP 66.171.180.48 > 72.20.23.24: ICMP 66.171.180.48 udp > > port 53 unreachable, length 74 > > 10:35:02.726303 IP 72.20.23.19.53 > 66.171.180.48.53: 952+ [1au] ANY? > > ripe.net. (38) > > 10:35:02.863667 IP 72.20.23.24.53 > 66.171.180.48.53: 952+ [1au] ANY? > > ripe.net. (38) > > 10:35:03.023693 IP 72.20.23.19.53 > 66.171.180.48.53: 952+ [1au] ANY? > > ripe.net. (38) > > 10:35:03.251935 IP 72.20.23.24.53 > 66.171.180.48.53: 952+ [1au] ANY? > > ripe.net. (38) > > 10:35:03.251964 IP 66.171.180.48 > 72.20.23.24: ICMP 66.171.180.48 udp > > port 53 unreachable, length 74 > > 10:35:03.326562 IP 72.20.23.19.53 > 66.171.180.48.53: 952+ [1au] ANY? > > ripe.net. (38) > > 10:35:03.630514 IP 72.20.23.24.53 > 66.171.180.48.53: 952+ [1au] ANY? > > ripe.net. (38) > > 10:35:03.638327 IP 72.20.23.19.53 > 66.171.180.48.53: 952+ [1au] ANY? > > ripe.net. (38) > > > > Note that the server involved does not run a DNS daemon, or listen on 53, > > or anything else that would attract attention. > > > > > > > > >