Add the DNS ERRORS section to the man page, in preparation for the dns library bump.

[haeredes.git] / doc / man1 / haeredes.1

diff --git a/doc/man1/haeredes.1 b/doc/man1/haeredes.1
index 31eeff72981584441d4d998a2ebc6cfb25f0d75f..a614993342201c16d6da9e68baf227922d97b315 100644 (file)
--- a/doc/man1/haeredes.1
+++ b/doc/man1/haeredes.1
@@ -59,7 +59,9 @@ 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:
+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
@@ -79,17 +81,49 @@ 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.
 .SH OPTIONS
 
 .IP \fB\-\-no\-append\-root\fR,\ \fB-n\fR
 Don't append a trailing dot to any DNS names. If you know what you're
 doing, this can be used to check relative results. Otherwise, it will
 probably just lead to false positives.
-.SH EXAMPLES
-
 .IP \fB\-\-server\fR,\ \fB-s\fR
 Use the given DNS server rather than the resolvers listed in
 /etc/resolv.conf. Either an IP address or a hostname will work.
+.IP \fB\-\-timeout\fR,\ \fB-t\fR
+The number of seconds to wait for an answer from DNS (default: 15).
 .SH EXAMPLES
 
 .IP \[bu] 2
@@ -99,6 +133,19 @@ Make sure example.com has the expected name servers,
 .nf
 .I $ haeredes a.iana-servers.net b.iana-servers.net <<< \(dqexample.com\(dq
 .fi
+
+.IP \[bu] 2
+If you use \-\-no\-append\-root and your nameservers are rooted, you
+must remember to supply the trailing dot yourself. Otherwise, you'll
+get false positives.
+
+.nf
+.I $ haeredes \-\-no\-append\-root \\\\
+.I "          a.iana-servers.net b.iana-servers.net" \\\\
+.I "          <<< \(dqexample.com\(dq"
+Domain \(dqexample.com\(dq delegates somewhere else:
+\(dqb.iana-servers.net.\(dq \(dqa.iana-servers.net.\(dq
+.fi
 .IP \[bu]
 Check orlitzky.com against the expected name servers, using
 a root nameserver (this checks the registrar configuration):