nanog mailing list archives
Re: large organization nameservers sending icmp packets to dns servers.
From: "Jason J. W. Williams" <williamsjj () digitar com>
Date: Tue, 7 Aug 2007 12:19:45 -0600
Hi Donald, I'm not prepared to call it stupid, but you're right it can cause issues. -J -------------------- Sent via BlackBerry ----- Original Message ----- From: Donald Stahl <don () calis blacksun org> To: Jason J. W. Williams Cc: Valdis.Kletnieks () vt edu <Valdis.Kletnieks () vt edu>; John Levine <johnl () iecc com>; nanog () nanog org <nanog () nanog org> Sent: Tue Aug 07 12:14:11 2007 Subject: RE: large organization nameservers sending icmp packets to dns servers.
All things being equal (which they're usually not) you could use the ACK response time of the TCP handshake if they've got TCP DNS resolution available. Though again most don't for security reasons...
Then most are incredibly stupid. Several anti DoS utilities force unknown hosts to initiate a query via TCP in order to be whitelisted. If the host can't perform a TCP query then they get blacklisted. In addition, any UDP truncated response needs to be retried via TCP- blocking it would cause a variety of problems. -Don !SIG:46b8b686156533728213125!
Current thread:
- Re: large organization nameservers sending icmp packets to dns servers., (continued)
- Re: large organization nameservers sending icmp packets to dns servers. Steve Atkins (Aug 06)
- Re: large organization nameservers sending icmp packets to dns servers. Valdis . Kletnieks (Aug 06)
- Re: large organization nameservers sending icmp packets to dns servers. Leigh Porter (Aug 06)
- Re: large organization nameservers sending icmp packets to dns servers. Owen DeLong (Aug 06)
- Message not available
- Re: large organization nameservers sending icmp packets to dns servers. Valdis . Kletnieks (Aug 06)
- Re: large organization nameservers sending icmp packets to dns servers. Patrick W. Gilmore (Aug 06)
- Re: large organization nameservers sending icmp packets to dns servers. Mark Andrews (Aug 09)
- Re: large organization nameservers sending icmp packets to dns servers. Crist Clark (Aug 10)
- Re: large organization nameservers sending icmp packets to dns servers. Mark Andrews (Aug 10)