diff --git a/config/production/config.yaml b/config/production/config.yaml
index dbf8547..4922af1 100644
--- a/config/production/config.yaml
+++ b/config/production/config.yaml
@@ -3,6 +3,7 @@ admins:
     - Paulo Meirelles
     - paulo@softwarelivre.org
 external_hostname: beta.softwarepublico.gov.br
+external_ip: 164.41.9.49
 site_url: https://beta.softwarepublico.gov.br
 colab_from_address: '"Portal do Software Publico" <noreply@beta.softwarepublico.gov.br>'
 server_email: '"Portal do Software Publico" <noreply@beta.softwarepublico.gov.br>'
@@ -10,5 +11,6 @@ email_subject_prefix: '[spb]'
 lists_hostname: listas.softwarepublico.gov.br
 lists_admin: paulo@softwarelivre.org
 relay_hostname: relay.softwarepublico.gov.br
+relay_ip: 164.41.9.48
 alt_ssh_port: 55555
 from_address: noreply@softwarepublico.gov.br
diff --git a/test/config_helper.sh b/test/config_helper.sh
new file mode 100644
index 0000000..c2ad0af
--- /dev/null
+++ b/test/config_helper.sh
@@ -0,0 +1,6 @@
+# exports all configuration variables into the environment with a config_
+# prefix, e.g.
+#
+# external_hostname → $config_external_hostname
+
+eval $(sed -e '/^\S*:\s*\S\+/!d; s/^/config_/; s/:\s*/=/' ${ROOTDIR:-.}/config/${SPB_ENV:-local}/config.yaml)
diff --git a/test/dns_test.sh b/test/dns_test.sh
new file mode 100644
index 0000000..ef6a2b7
--- /dev/null
+++ b/test/dns_test.sh
@@ -0,0 +1,107 @@
+. $(dirname $0)/test_helper.sh
+
+if [ "$SPB_ENV" = local ]; then
+  echo "_No DNS for local environment_"
+  exit
+fi
+
+
+export LANG=C
+
+check_hostname() {
+  local host="$1"
+  local ip="$2"
+  local results="$(host -t A $host)"
+  local expected="$host has address $ip"
+  assertEquals "$host must resolve to $ip" "$results" "$expected"
+}
+
+check_mx() {
+  local host="$1"
+  local mx="$2"
+  local results="$(host -t MX $host)"
+  local expected="$host mail is handled by 0 ${mx}."
+  assertEquals "$host MX must be $mx"  "$results" "$expected"
+}
+
+check_reverse_dns() {
+  local ip="$1"
+  local hostname="$2"
+  local results="$(host $ip)"
+  local expected=".*in-addr.arpa domain name pointer $hostname"
+  assertTrue "Reverse DNS of $ip must be $hostname (found: $results)" "expr match \"$results\$\" \"$expected\$\""
+}
+
+test_dns_web() {
+  check_hostname "$config_external_hostname" "$config_external_ip"
+}
+
+test_mx() {
+  check_mx "$config_external_hostname" "${config_relay_hostname}"
+}
+
+test_dns_lists() {
+  check_hostname "$config_lists_hostname" "$config_external_ip"
+}
+
+test_mx_lists() {
+  check_mx "$config_lists_hostname" "$config_relay_hostname"
+}
+
+test_dns_relay() {
+  check_hostname "$config_relay_hostname" "$config_relay_ip"
+}
+
+test_reverse_dns_web() {
+  check_reverse_dns "$config_external_ip" "$config_external_hostname"
+}
+
+test_reverse_dns_relay() {
+  check_reverse_dns "$config_relay_ip" "$config_relay_hostname"
+}
+
+# TODO test_spf_external_relay
+
+if [ "$1" = '--doc' ]; then
+  check_hostname() {
+    echo "| ❏ A | $1 | $2 |"
+  }
+  check_mx() {
+    echo "| ❏ MX | $1 | ${2}. |"
+  }
+  check_reverse_dns() {
+    echo "| ❏ PTR  | $1 | ${2}. |"
+  }
+  header() {
+    echo "## $1"
+    echo
+    echo '| Tipo | Entrada | Aponta para |'
+    echo '|:-----|:------|:----------|'
+  }
+  footer() {
+    echo
+  }
+  (
+    echo "# Entradas de DNS necessárias"
+    header 'DNS(A)'
+    test_dns_web
+    test_dns_lists
+    test_dns_relay
+    footer
+
+    header 'MX'
+    test_mx
+    test_mx_lists
+    footer
+
+    header 'DNS reverso'
+    test_reverse_dns_web
+    test_reverse_dns_relay
+    footer
+
+    # FIXME test_spf_external_relay
+
+  )
+else
+  . shunit2
+fi
diff --git a/test/test_helper.sh b/test/test_helper.sh
index cdbe640..fee9275 100644
--- a/test/test_helper.sh
+++ b/test/test_helper.sh
@@ -19,4 +19,5 @@ load_shunit2() {
 }
 
 . $(dirname $0)/ip_helper.sh
+. $(dirname $0)/config_helper.sh
 
--
libgit2 0.21.2