Re: DNS ACL ?

From: John Nemeth (jnemeth@victoria.tc.ca)
Date: Sat Nov 12 2005 - 16:09:43 EST


On Apr 3, 3:10am, John Hally wrote:
}
} I need a sanity check regarding DNS ACLs. For external facing DNS servers
} you need to allow only udp/53 inbound, correct? I know tcp/53 is used for

     No.

} zone transfers and requests/replies greater than a certain size, but they
} shouldn't typically happen for general dns queries correct?

     Depends on the size of the query. Which in turn depends on how
your DNS is setup (i.e. do you have hosts with a large number of A
records, do you have a number of MX records {queries for these usually
return the A records as 'Additional Info'}, or have AAAA records?).
Also, don't forget about your secondaries if they happen to be
offsite.

}-- End of excerpt from John Hally

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