doc/man1/haeredes.1

   1 .TH haeredes 1
   2
   3 .SH NAME
   4 haeredes \- Confirm delegation of NS and MX records.
   5 .SH SYNOPSIS
   6
   7 \fBhaeredes\fR [\fIOPTIONS\fR] [\fIDELEGATES\fR]
   8 .SH INPUT
   9 .P
  10 A list of domains, separated by whitespace.
  11 .SH OUTPUT
  12 .P
  13 A list of domains which don't have the supplied (expected) delegates
  14 listed as their NS/MX records.
  15 .SH DESCRIPTION
  16 .P
  17 Haeredes is primarily useful for ISP network administrators. Customers
  18 will occasionally decide to switch hosts without alerting the current
  19 host; this can cause two problems.
  20 .P
  21 With NS records, the previous host (at the very least) keeps hosting a
  22 DNS zone that does nothing. If that host uses their authoritative
  23 nameserver as a caching lookup server as well, it may return
  24 incorrect results to queries about the domain in question.
  25 .P
  26 For MX records, the situation is slightly worse. Most mail servers
  27 will immediately accept mail for which the server thinks it is the
  28 ultimate destination. If a mail server is configured as the
  29 destination for a domain, but it is not the MX for that domain, then
  30 mail submitted to that server may possibly be lost. It is therefore
  31 important to remove domains from the old mail host as soon as the MX
  32 record is changed.
  33 .P
  34 Haeredes can alert administrators when NS/MX records are changed.
  35 .SH NORMALIZATION
  36 .P
  37 By default, domain/hostnames given will be normalized in two ways:
  38 .IP \[bu] 2
  39 All names will be lowercased.
  40
  41 .IP \[bu]
  42 All names will have a trailing dot (the DNS root) appended if one is
  43 not present. This can be controlled with the
  44 \fB\-\-no\-append\-root\fR flag.
  45 .SH QUERY RESULTS
  46 .P
  47 When Haeredes makes a query for an MX record, the result is parsed
  48 from the \(dqanswer\(dq section of the response. This is
  49 straightforward.
  50 .P
  51 For NS records, however, there are two sections that may contain
  52 results. If you query the authoritative nameservers for example.com,
  53 they will return the response in the \(dqanswer\(dq section, as with
  54 MX records:
  55
  56 .nf
  57 .I $ dig +short @a.iana-servers.net example.com NS
  58 b.iana-servers.net.
  59 a.iana-servers.net.
  60 .fi
  61 .P
  62 However, if you ask a root server, they will return the response in
  63 another section, called \(dqauthority\(dq. The \(dqanswer\(dq section
  64 is empty:
  65
  66 .nf
  67 .I $ dig +short @a.gtld-servers.net example.com NS
  68 .fi
  69 .P
  70 We have to request the \(dqauthority\(dq section explicitly:
  71
  72 .nf
  73 .I $ dig +noall +authority @a.gtld-servers.net example.com NS
  74 example.com.            172800  IN      NS      a.iana-servers.net.
  75 example.com.            172800  IN      NS      b.iana-servers.net.
  76 .fi
  77 .P
  78 Given Haeredes' use case, it is useful to combine the two. You can
  79 query a root server to check the registrar data, or a recursive
  80 resolver to check the data on the authoritative nameservers.
  81 .P
  82 So that's what we do. In NS mode, Haeredes will check both the
  83 \(dqanswer\(dq and \(dqauthority\(dq sections for results.
  84 .SH PARALLEL QUERIES
  85 .P
  86 Haeredes can use multiple threads to perform its queries. It will use
  87 a number of threads equal to the number of processors available to the
  88 GHC runtime. This can be changed with the \fI+RTS \-N\fR flag. For
  89 example, to use 10 threads,
  90
  91 .nf
  92 $ haeredes [OPTIONS] [DELEGATES] \fI+RTS -N10\fR
  93 .fi
  94 .SH DNS ERRORS
  95 .P
  96 There are three types of DNS errors that can occur:
  97 .nr step 1 1
  98 .IP \n[step] 2
  99 Timeouts. If the query times out, we don't get an answer back. The
 100 timeout can be adjusted with the \fB\-\-timeout\fR flag.
 101 .IP \n+[step]
 102 Sequence number mismatches. Every DNS query is sent with a sequence
 103 number; if the response has a different sequence number than the one
 104 we sent, something is wrong (foul play, or a bug somewhere in the
 105 stack).
 106 .IP \n+[step]
 107 Unexpected RDATA. If we ask for an \fIA\fR record, we expect to get a
 108 response for an \fIA\fR record. If we get something else -- well,
 109 something went wrong.
 110 .P
 111 Haeredes is designed to ignore these errors. A timeout or bad response
 112 to a query is not an indication that something is wrong with the DNS
 113 for the supplied domains. There might be something else wrong with
 114 your (caching/recursive) DNS infrastructure, but it isn't one of the
 115 problems that Haeredes is designed to detect.
 116 .SH OPTIONS
 117
 118 .IP \fB\-\-no\-append\-root\fR,\ \fB-n\fR
 119 Don't append a trailing dot to any DNS names. If you know what you're
 120 doing, this can be used to check relative results. Otherwise, it will
 121 probably just lead to false positives.
 122 .IP \fB\-\-server\fR,\ \fB-s\fR
 123 Use the given DNS server rather than the resolvers listed in
 124 /etc/resolv.conf. Either an IP address or a hostname will work.
 125 .IP \fB\-\-timeout\fR,\ \fB-t\fR
 126 The number of seconds to wait for an answer from DNS (default: 15).
 127 .SH EXAMPLES
 128
 129 .IP \[bu] 2
 130 Make sure example.com has the expected name servers,
 131 [ab].iana-servers.net:
 132
 133 .nf
 134 .I $ haeredes a.iana-servers.net b.iana-servers.net <<< \(dqexample.com\(dq
 135 .fi
 136
 137 .IP \[bu] 2
 138 If you use \-\-no\-append\-root and your nameservers are rooted, you
 139 must remember to supply the trailing dot yourself. Otherwise, you'll
 140 get false positives.
 141
 142 .nf
 143 .I $ haeredes \-\-no\-append\-root \\\\
 144 .I "          a.iana-servers.net b.iana-servers.net" \\\\
 145 .I "          <<< \(dqexample.com\(dq"
 146 Domain \(dqexample.com\(dq delegates somewhere else:
 147 \(dqb.iana-servers.net.\(dq \(dqa.iana-servers.net.\(dq
 148 .fi
 149 .IP \[bu]
 150 Check orlitzky.com against the expected name servers, using
 151 a root nameserver (this checks the registrar configuration):
 152
 153 .nf
 154 .I $ haeredes --server d.gtld-servers.net dns1.viabit.com dns2.viabit.com \\\\
 155 .I "           <<< \(dqorlitzky.com\(dq"
 156 .fi
 157 .IP \[bu]
 158 Check orlitzky.com against only one of the expected two nameservers:
 159
 160 .nf
 161 .I $ haeredes dns1.viabit.com <<< \(dqorlitzky.com\(dq
 162 Domain \(dqorlitzky.com.\(dq delegates somewhere else: \
 163 \(dqdns2.viabit.com.\(dq
 164 .fi
 165 .IP \[bu]
 166 Check a nonexistent domain (we provide no delegates, since we
 167 know .invalid will not be delegated):
 168
 169 .nf
 170 .I $ haeredes <<< \(dqexample.invalid\(dq
 171 Domain \(dqexample.invalid.\(dq not delegated.
 172 .fi
 173 .IP \[bu]
 174 Set the timeout to one second, and query a nonexistent
 175 nameserver. This should result in a timeout, which will be ignored per
 176 the discussion in \fBDNS ERRORS\fR:
 177
 178 .nf
 179 .I $ haeredes --timeout=1 --server 10.1.46.12 ns1.example.com \\\\
 180 .I "           <<< \(dqexample.com\(dq"
 181 .fi
 182 .SH BUGS
 183 .P
 184 Send bugs to michael@orlitzky.com.