No, we don't actually perform a dns request, as that wouldn't be measuring the network latency, we simply start a timer, wait for the tcp connection to negotiate, and stop the timer. The connection is then closed. Currently we do this every 2 minutes, which shouldn't be perceived as an attack of any kind by a large nameserver, or at least no more so then sending icmp echo's to their routers :) Matt -- Matt Levine, CTO <mlevine@efront.com> eFront Media, Inc. - http://www.efront.com Phone: +1 714 428 8500 ext. 504 Fax : +1 949 203 2156 ICQ : 17080004 -----Original Message----- From: owner-nanog@merit.edu [mailto:owner-nanog@merit.edu]On Behalf Of Miguel A.L. Paraz Sent: Monday, December 18, 2000 1:38 AM To: nanog@merit.edu Subject: Re: Pinging routers for network status On Mon, Dec 18, 2000 at 01:12:17AM -0800, Matt Levine wrote:
Well, although there's no entirely fool-proof way, We've found a better way of monitoring "real" outages/issues is to monitor the time required to setup a tcp connection to some "trusted" machines. For example, in our VA datacenter we monitor the time required to setup a connection with tier1 providers (UU,BBN,DIGEX for example) nameservers (on port 53).. We've found it slightly more reliable than ICMP reqs, especially since when routers get busy, it shows as degradation vs. outage.
How does your "DNS ping" work, do you just open and close a TCP connection? Or make actual requests? Like, "dig soa provider.net @ns.provider.net". But perhaps if everyone starts doing this to the same box, it could be seen as DoS? -- http://www.internet.org.ph Internet and ISP's in the Philippines http://www.ASARproject.org Artists for Social Action and Response GSM Mobile: +63-917-810-9728