>> You're thinking that the rate limit is intended to protect YOUR server. >> It's actually to prevent your server from being used as a reflector to >> attack some OTHER server. The spoofed addresses all point to that >> server.
>Sorry I just can't understand that why my server is being used to attack >other's servers? People (bad people) spoof a query source (the victims address) and fire a query at your server. If your server allows queries from the Internet (etc), then it will reply to the victim. Generally speaking, the query is smaller than the reply, so the attacker uses your server to amplify the attack, which is why this is a DNS amplification attack. If you do this at 50qps from 10,000 botnet servers, you can generate a lot of traffic very easily, for a very small investment. This attack relies on open resolvers on the internet, so if you don't need your DNS server to be queried by the entire internet, throw an ACL in front of it/on it and limit who can talk to you. Because I like pictures, here's a simple one to show what I'm getting at: http://infosecurity.jp/wp-content/uploads/2011/02/113.jpg Hope that helps. t. --------------------------------------------------------------------- This transmission (including any attachments) may contain confidential information, privileged material (including material protected by the solicitor-client or other applicable privileges), or constitute non-public information. Any use of this information by anyone other than the intended recipient is prohibited. If you have received this transmission in error, please immediately reply to the sender and delete this information from your system. Use, dissemination, distribution, or reproduction of this transmission by unintended recipients is not authorized and may be unlawful. _______________________________________________ Please visit https://lists.isc.org/mailman/listinfo/bind-users to unsubscribe from this list bind-users mailing list bind-users@lists.isc.org https://lists.isc.org/mailman/listinfo/bind-users
