+.SH NORMALIZATION
+.P
+By default, domain/hostnames given will be normalized in two ways:
+.IP \[bu] 2
+All names will be lowercased.
+
+.IP \[bu]
+All names will have a trailing dot (the DNS root) appended if one is
+not present. This can be controlled with the
+\fB\-\-no\-append\-root\fR flag.
+.SH QUERY RESULTS
+.P
+When Haeredes makes a query for an MX record, the result is parsed
+from the \(dqanswer\(dq section of the response. This is
+straightforward.
+.P
+For NS records, however, there are two sections that may contain
+results. If you query the authoritative nameservers for example.com,
+they will return the response in the \(dqanswer\(dq section, as with
+MX records:
+
+.nf
+.I $ dig +short @a.iana-servers.net example.com NS
+b.iana-servers.net.
+a.iana-servers.net.
+.fi
+.P
+However, if you ask a root server, they will return the response in
+another section, called \(dqauthority\(dq. The \(dqanswer\(dq section
+is empty:
+
+.nf
+.I $ dig +short @a.gtld-servers.net example.com NS
+.fi
+.P
+We have to request the \(dqauthority\(dq section explicitly:
+
+.nf
+.I $ dig +noall +authority @a.gtld-servers.net example.com NS
+example.com. 172800 IN NS a.iana-servers.net.
+example.com. 172800 IN NS b.iana-servers.net.
+.fi
+.P
+Given Haeredes' use case, it is useful to combine the two. You can
+query a root server to check the registrar data, or a recursive
+resolver to check the data on the authoritative nameservers.
+.P
+So that's what we do. In NS mode, Haeredes will check both the
+\(dqanswer\(dq and \(dqauthority\(dq sections for results.
+.SH PARALLEL QUERIES
+.P
+Haeredes can use multiple threads to perform its queries. It will use
+a number of threads equal to the number of processors available to the
+GHC runtime. This can be changed with the \fI+RTS \-N\fR flag. For
+example, to use 10 threads,
+
+.nf
+$ haeredes [OPTIONS] [DELEGATES] \fI+RTS -N10\fR
+.fi
+.SH DNS ERRORS
+.P
+There are three types of DNS errors that can occur:
+.nr step 1 1
+.IP \n[step] 2
+Timeouts. If the query times out, we don't get an answer back. The
+timeout can be adjusted with the \fB\-\-timeout\fR flag.
+.IP \n+[step]
+Sequence number mismatches. Every DNS query is sent with a sequence
+number; if the response has a different sequence number than the one
+we sent, something is wrong (foul play, or a bug somewhere in the
+stack).
+.IP \n+[step]
+Unexpected RDATA. If we ask for an \fIA\fR record, we expect to get a
+response for an \fIA\fR record. If we get something else -- well,
+something went wrong.
+.P
+Haeredes is designed to ignore these errors. A timeout or bad response
+to a query is not an indication that something is wrong with the DNS
+for the supplied domains. There might be something else wrong with
+your (caching/recursive) DNS infrastructure, but it isn't one of the
+problems that Haeredes is designed to detect.