hotfix: changed DomRobot API behaviour

CHANGELOG.md

@@ -1,6 +1,55 @@
 # Changelog
 
 
+## 0.5.3 (2023-02-26)
+
+### Fix
+
+* Set constant alpine version as latest couses issues. [Eduard Veit]
+
+
+## 0.5.2 (2023-02-26)
+
+### Fix
+
+* Incorrect dns ip handling via domrobot. [Eduard Veit]
+
+
+## 0.5.1 (2022-11-21)
+
+### Features
+
+* Use provider checkip API. [Eduard Veit]
+
+### Fix
+
+* Handle some curl exit codes. [Eduard Veit]
+
+
+## 0.5.0 (2022-11-10)
+
+### Features
+
+* Use provider DNS servers. [Eduard Veit]
+
+* Temporarily disable an ip version if the connectivity/routing does not work. [Eduard Veit]
+
+### Documentation
+
+* 📝 update default values in table. [Eduard Veit]
+
+
+## 0.4.0 (2022-11-07)
+
+### Features
+
+* ✨ add support for dynu.com as DynDNS2 provider. [Eduard Veit]
+
+### Documentation
+
+* 📝 add dynu.com as DynDNS2 provider. [Eduard Veit]
+
+
 ## 0.3.5 (2022-11-03)
 
 ### Features

Dockerfile

@@ -1,4 +1,4 @@
-FROM alpine:latest
+FROM alpine:3.16.4
 
 RUN \
 apk update \

README.md

@@ -23,15 +23,16 @@ IPv4 (A) and IPv6 (AAAA) record updates are supported.
 
 The following update methods are currently implemented:
 
-| Provider            | API                   | TTL in seconds | Credentials                                                                                  | own domain via NS record | free (sub-) domain                             |
+| Provider            | API                   | TTL in seconds | Credentials                                                                                  | own domain via NS record                 | free (sub-) domain                   |
-|---------------------|-----------------------|----------------|----------------------------------------------------------------------------------------------|--------------------------|------------------------------------------------|
+|---------------------|-----------------------|----------------|----------------------------------------------------------------------------------------------|------------------------------------------|--------------------------------------|
-| INWX.com            | Domrobot JSON-RPC-API | 300            | customer login `username` & `password`. Mobile TAN (OTP) is currently not supported by DynB. | ✔️                       | ⛔ choose one of your owned domains             |
+| INWX.com            | Domrobot JSON-RPC-API | 300            | customer login `username` & `password`. Mobile TAN (OTP) is currently not supported by DynB. | ✔️ 🆓 for your registered domains @ inwx | ⛔ for your registered domains @ inwx |
-| INWX.com            | DynDNS2               | 60             | specific dyndns `username` & `password`                                                      | ✔️                       | ⛔ choose one of your owned domains per account |
+| INWX.com            | DynDNS2               | 60             | specific dyndns `username` & `password`                                                      | ✔️ 🆓 for your registered domains @ inwx | ⛔ for your registered domains @ inwx |
-| deSEC.io (dedyn.io) | DynDNS2               | 60             | `token`                                                                                      | ✔️                       | ✔️                                             |
+| deSEC.io (dedyn.io) | DynDNS2               | 60             | `token`                                                                                      | ✔️ 🆓                                    | ✔️                                   |
-| DuckDNS.org         | DynDNS2               | 60             | `token`                                                                                      | ⛔                        | ✔️                                             |
+| DuckDNS.org         | DynDNS2               | 60             | `token`                                                                                      | ⛔                                        | ✔️                                   |
-| dynv6.com           | DynDNS2               | 60             | `token`                                                                                      | ✔️                       | ✔️                                             |
+| dynv6.com           | DynDNS2               | 60             | `token`                                                                                      | ✔️ 🆓                                    | ✔️                                   |
-| ddnss.de            | DynDNS2               | 10             | update key as `token`                                                                        | ⛔                        | ✔️                                             |
+| ddnss.de            | DynDNS2               | 10             | `update key` as `token`                                                                      | ⛔                                        | ✔️                                   |
-| IPv64.net           | DynDNS2               | 60             | `DynDNS Updatehash` as `token`                                                               | ⛔                        | ✔️                                             |
+| IPv64.net           | DynDNS2               | 60             | `DynDNS Updatehash` as `token`                                                               | ✔️ 💲                                    | ✔️                                   |
+| dynu.com            | DynDNS2               | 30             | `username` & `password`                                                                      | ✔️ 🆓                                    | ✔️                                   |
 
 ## 📦 Requirements
 
@@ -173,17 +174,17 @@ services:
 
 ## environment variables
 
-| variable              | default value   | description                                                                                                    |
+| variable              | default value                                                                                                                  | description                                                                                                    |
-|-----------------------|-----------------|----------------------------------------------------------------------------------------------------------------|
+|-----------------------|--------------------------------------------------------------------------------------------------------------------------------|----------------------------------------------------------------------------------------------------------------|
-| DYNB_DYN_DOMAIN       | undefined       | required; `dyndns.example.com`                                                                                 |
+| DYNB_DYN_DOMAIN       | undefined                                                                                                                      | required; `dyndns.example.com`                                                                                 |
-| DYNB_SERVICE_PROVIDER | undefined       | required; `deSEC`, `duckdns`, `dynv6`, `inwx`, `ddnss`, `ipv64`                                                |
+| DYNB_SERVICE_PROVIDER | undefined                                                                                                                      | required; `deSEC`, `duckdns`, `dynv6`, `inwx`, `ddnss`, `ipv64`                                                |
-| DYNB_UPDATE_METHOD    | undefined       | required; `dyndns` or `domrobot` (with inwx)                                                                   |
+| DYNB_UPDATE_METHOD    | undefined                                                                                                                      | required; `dyndns` or `domrobot` (with inwx)                                                                   |
-| DYNB_IP_MODE          | undefined       | required; `4`, `6` or `64` for both                                                                            |
+| DYNB_IP_MODE          | undefined                                                                                                                      | required; `4`, `6` or `64` for both                                                                            |
-| DYNB_USERNAME         | undefined       | the requirement depends on your provider and the update method                                                 |
+| DYNB_USERNAME         | undefined                                                                                                                      | the requirement depends on your provider and the update method                                                 |
-| DYNB_PASSWORD         | undefined       | the requirement depends on your provider and the update method                                                 |
+| DYNB_PASSWORD         | undefined                                                                                                                      | the requirement depends on your provider and the update method                                                 |
-| DYNB_TOKEN            | undefined       | the requirement depends on your provider and the update method                                                 |
+| DYNB_TOKEN            | undefined                                                                                                                      | the requirement depends on your provider and the update method                                                 |
-| DYNB_INTERVAL         | undefined       | without this setting the script/docker container will run one time and exits                                   |
+| DYNB_INTERVAL         | undefined                                                                                                                      | without this setting the script/docker container will run one time and exits                                   |
-| DYNB_DEBUG            | undefined       | more console outputs                                                                                           |
+| DYNB_DEBUG            | undefined                                                                                                                      | more console outputs                                                                                           |
-| DYNB_IPv4_CHECK_SITE  | api64.ipify.org | You need a website or Web-API that outputs your remote IP                                                      |
+| DYNB_IPv4_CHECK_SITE  | tries in this order `ip64.ev21.de` (anonymous logging for 7 days), `api64.ipify.org`, `api.my-ip.io/ip`, `ip.anysrc.net/plain` | You need a website or Web-API that outputs your remote IP                                                      |
-| DYNB_IPv6_CHECK_SITE  | api64.ipify.org | You need a website or Web-API that outputs your remote IP                                                      |
+| DYNB_IPv6_CHECK_SITE  | tries in this order `ip64.ev21.de` (anonymous logging for 7 days), `api64.ipify.org`, `api.my-ip.io/ip`, `ip.anysrc.net/plain` | You need a website or Web-API that outputs your remote IP                                                      |
-| DYNB_DNS_CHECK_SERVER | undefined       | If you are using a local DNS Resolver/Server make sure it answers with the public answer or set another server |
+| DYNB_DNS_CHECK_SERVER | using the DynDNS2 providers DNS servers                                                                                        | If you are using a local DNS Resolver/Server make sure it answers with the public answer or set another server |

dynb.sh

@@ -12,67 +12,76 @@
 
 #DYNB_DYN_DOMAIN=
 
-## service provider could be deSEC, duckdns, dynv6, inwx
+# service provider could be deSEC, duckdns, dynv6, inwx
 #DYNB_SERVICE_PROVIDER=
 
 ## update method options: domrobot, dyndns
 #DYNB_UPDATE_METHOD=
 
-## ip mode could be either: 4, 6 or dual for dualstack
+# ip mode could be either: 4, 6 or dual for dualstack
 #DYNB_IP_MODE=
 
-## If you are using the DomRobot RPC-API enter your credentials for the web interface login here
+# If you are using the DomRobot RPC-API enter your credentials for the web interface login here
-## If you are using the DynDNS2 protocol enter your credentials here
+# If you are using the DynDNS2 protocol enter your credentials here
 #DYNB_USERNAME=
 #DYNB_PASSWORD=
-## or use a token
+# or use a token
 #DYNB_TOKEN=
 
-## TTL (time to live) for the DNS record
+# TTL (time to live) for the DNS record
-## This setting is only relevant for API based record updates (not DnyDNS2!)
+# This setting is only relevant for API based record updates (not DnyDNS2!)
-## minimum allowed TTL value by inwx is 300 (5 minutes)
+# minimum allowed TTL value by inwx is 300 (5 minutes)
 TTL=300
 
-## The IP-Check sites (some sites have different urls for v4 and v6)
+# The IP-Check sites (some sites have different urls for v4 and v6)
-## Pro tip: use your own ip check server for privacy
+# Pro tip: use your own ip check server for privacy
-## it could be as simple as that...
+# it could be as simple as that...
-## create an index.php with <?php echo $_SERVER'REMOTE_ADDR'; ?>
+# create an index.php with <?php echo $_SERVER'REMOTE_ADDR'; ?>
-_ipv4_checker=api64.ipify.org
+#DYNB_IPv4_CHECK_SITE=
-_ipv6_checker=api64.ipify.org
+#DYNB_IPv6_CHECK_SITE=
 
-## An exernal DNS check server prevents wrong info from local DNS servers/resolvers
+# An exernal DNS check server prevents wrong info from local DNS servers/resolvers
-_DNS_checkServer=
+#DYNB_DNS_CHECK_SERVER=9.9.9.9
 
-## if you are actively using multiple network interfaces you might want to specify this
+# if you are actively using multiple network interfaces you might want to specify this
-## normally the default value is okay
+# normally the default value is okay
 #_network_interface=eth0
 _network_interface=
 
 ######################################################
 ## You don't need to change the following variables ##
+
 _INWX_JSON_API_URL=https://api.domrobot.com/jsonrpc/
 _internet_connectivity_test_server=https://www.google.de
-_new_IPv4=
+_default_check_ip_servers=("ip64.ev21.de" "api64.ipify.org" "api.my-ip.io/ip" "ip.anysrc.net/plain")
-_new_IPv6=
+_ipv4_checker=
+_ipv6_checker=
+_DNS_checkServer=
+_remote_IPv4=
+_remote_IPv6=
 _dns_records=
 _main_domain=
 _is_IPv4_enabled=false
 _is_IPv6_enabled=false
 _interface_str=
-_status=
 _eventTime=0
 _errorCounter=0
 _response=
 _statusHostname=
 _statusUsername=
 _statusPassword=
-_version=0.3.5
+_version=0.5.3
 _userAgent="DynB/$_version github.com/EV21/dynb"
 _configFile=$HOME/.local/share/dynb/.env
 _statusFile=/tmp/dynb.status
-_debug=0
+_debug=false
 _minimum_looptime=60
-_loopMode=0
+_loopMode=false
+_remote_ip=
+_dns_ip=
+_has_remote_ip_error=
+_has_remote_ip4=false
+_has_remote_ip6=false
 
 # Ansi color code variables
 yellow_color="\e[0;33m"
@@ -103,9 +112,30 @@ function is_IPv6_address
   fi
 }
 
+## is_ip_address A B
+# parameters required
+# 1. param: ip_version
+# 2. param: ip_address
+function is_ip_address
+{
+  local ip_version=$1
+  local ip_address=$2
+  case $ip_version in
+    4)
+      is_IPv4_address "$ip_address"
+      result=$?
+    ;;
+    6)
+      is_IPv6_address "$ip_address"
+      result=$?
+    ;;
+  esac
+  return "$result"
+}
+
 function loopMode
 {
-  if [[ $_loopMode -eq 1 ]]
+  if [[ $_loopMode == "true" ]]
   then return 0
   else return 1
   fi
@@ -113,7 +143,7 @@ function loopMode
 
 function debugMode
 {
-  if [[ $_debug -eq 1 ]]
+  if [[ $_debug == "true" ]]
   then return 0
   else return 1
   fi
@@ -186,37 +216,145 @@ function fetchDNSRecords
   _dns_records=$(echo "$_response" | jq '.resData.record[]')
 }
 
+## getRecordID
 # requires parameter A or AAAA
 # result to stdout
 function getRecordID
 {
   echo "$_dns_records" |
-    jq "select(.type == \"${1}\") | .id"
+    jq --raw-output "select(.type == \"${1}\") | .id"
 }
 
-# requires parameter A or AAAA
+## do_dig_request A B
-# result to stdout
+# sets variable: _dns_ip
+#
+# requires parameter
+# 1. param: dns server address
+# 2. param: A or AAAA
+function do_dig_request
+{
+  local dns_server=$1
+  local record_type=$2
+  dig_response=$(dig @"$dns_server" in "$record_type" +short "$DYNB_DYN_DOMAIN" 2>&1)
+  dig_exitcode=$?
+  if [[ $dig_exitcode -gt 0 ]]
+  then
+    errorMessage "DNS request for $record_type @ $dns_server failed with exit code: $dig_exitcode $dig_response"
+    unset _dns_ip
+    return 1
+  else
+    case $record_type in
+    A) is_ip_address 4 "$dig_response"
+    ;;
+    AAAA) is_ip_address 6 "$dig_response"
+    ;;
+    esac
+    if test $? -gt 0
+    then
+      test -n "$dig_response" || debugMessage "dig response: $dig_response"
+      unset _dns_ip
+      return 1
+    fi
+  fi
+  # If the dns resolver lists multiple records in the answer section we filter the first line
+  # using short option "-n" and not "--lines" because of alpines limited BusyBox head command
+  _dns_ip=$(echo "$dig_response" | head -n 1)
+  return 0
+}
+
+## getDNSIP A
+# sets variable: _dns_ip
+#
+# requires parameter
+# 1. param: A or AAAA
 function getDNSIP() {
-  echo "$_dns_records" |
+  local record_type=$1
-    jq --raw-output "select(.type == \"${1}\") | .content"
+  if [[ $DYNB_UPDATE_METHOD == domrobot ]]
+  then
+    _dns_ip=$(echo "$_dns_records" |
+      jq --raw-output "select(.type == \"${record_type}\") | .content")
+  else
+    for current_dns_server in "${provider_dns_servers[@]}"
+    do
+      debugMessage "try dig DNS request with record type $record_type @$current_dns_server"
+      if do_dig_request "$current_dns_server" "$record_type"
+      then break
+      fi
+    done
+  fi
 }
 
+## getRemoteIP A
+# sets variable: _remote_ip,
+#
 # requires parameter
 # 1. param: 4 or 6 for ip version
-# 2. param: IP check server address
+#
 # result to stdout
 function getRemoteIP
 {
   local ip_version=$1
-  local ip_check_server=$2
+
-  curl --silent "$_interface_str" --user-agent "$_userAgent" \
+  if test -n "$_provider_check_ip"
-    --ipv"${ip_version}" --location "${ip_check_server}"
+  then ip_check_servers=("$_provider_check_ip" "${_default_check_ip_servers[@]}")
-  local curls_status_code=$?
-  # shellcheck disable=2181
-  if [[ $curls_status_code -gt 0 ]]; then
-    errorMessage "IPCheck (getRemoteIP $ip_version) request failed"
-    exit 1
   fi
+  case $ip_version in
+    4)
+      if test -n "$_ipv4_checker"
+      then ip_check_servers=("$_ipv4_checker" "${_default_check_ip_servers[@]}")
+      else ip_check_servers=("${_default_check_ip_servers[@]}")
+      fi
+    ;;
+    6)
+      if test -n "$_ipv6_checker"
+      then ip_check_servers=("$_ipv6_checker" "${_default_check_ip_servers[@]}")
+      else ip_check_servers=("${_default_check_ip_servers[@]}")
+      fi
+    ;;
+  esac
+
+  for current_check_server in "${ip_check_servers[@]}"
+  do
+    debugMessage "try getting remote IPv$ip_version via $current_check_server"
+    response=$(curl --silent "$_interface_str" --user-agent "$_userAgent" \
+    --ipv"${ip_version}" --location "${current_check_server}")
+    curls_status_code=$?
+    # shellcheck disable=2181
+    if [[ $curls_status_code -gt 0 ]]
+    then
+      errorMessage "Remote IPv$ip_version request @ ${current_check_server} failed with curl status code: $curls_status_code"
+      _has_remote_ip_error=true
+      return_value=1
+    else
+      if is_ip_address "$ip_version" "$response"
+      then
+        _has_remote_ip_error=false
+        _remote_ip="$response"
+        return_value=0
+        break
+      else
+        errorMessage "The response from the IP check server $current_check_server is not an IPv$ip_version address: $response"
+        _has_remote_ip_error=true
+        return_value=1
+      fi
+    fi
+  done
+
+  case $ip_version in
+  4)
+    if [[ $_has_remote_ip_error == true ]]
+    then _has_remote_ip4=false
+    else _has_remote_ip4=true
+    fi
+  ;;
+  6)
+    if [[ $_has_remote_ip_error == true ]]
+    then export _has_remote_ip6=false
+    else export _has_remote_ip6=true
+    fi
+  ;;
+  esac
+  return "$return_value"
 }
 
 # requires parameter
@@ -227,12 +365,12 @@ function updateRecord
   if [[ ${ip_version} == 4 ]]
   then
     ID=$(getRecordID A)
-    IP=$_new_IPv4
+    IP=$_remote_IPv4
   fi
   if [[ ${ip_version} == 6 ]]
   then
     ID=$(getRecordID AAAA)
-    IP=$_new_IPv6
+    IP=$_remote_IPv6
   fi
   if [[ $IP != "" ]]
   then
@@ -258,93 +396,116 @@ function updateRecord
   fi
 }
 
-function select_update_base_url
+function prepare_request_parameters
 {
   # default parameter values
-  myip_str=myip
+  ipv4_parameter_name=myip
-  myipv6_str=myipv6
+  ipv6_parameter_name=myipv6
-
+  curl_parameters=("--user-agent" "$_userAgent")
-  INWX_DYNDNS_UPDATE_URL="https://dyndns.inwx.com/nic/update?"
-  DESEC_DYNDNS_UPDATE_URL="https://update.dedyn.io/?"
-  DUCKDNS_DYNDNS_UPDATE_URL="https://www.duckdns.org/update?domains=$DYNB_DYN_DOMAIN&token=$DYNB_TOKEN&"
-  DYNV6_DYNDNS_UPDATE_URL="https://dynv6.com/api/update?zone=$DYNB_DYN_DOMAIN&token=$DYNB_TOKEN&"
-  DDNSS_DYNDNS_UPDATE_URL="https://ddnss.de/upd.php?key=$DYNB_TOKEN&host=$DYNB_DYN_DOMAIN&"
-  IPV64NET_DYNDNS_UPDATE_URL="https://ipv64.net/nic/update?"
 
   case $DYNB_SERVICE_PROVIDER in
-    inwx* | INWX*)
+    [Ii][Nn][Ww][Xx]*)
-      dyndns_update_url=$INWX_DYNDNS_UPDATE_URL
+    # inwx.de
-      ;;
+    # in case of dualstack use you need to request both parameters with the same request
-    deSEC* | desec* | dedyn*)
+    # otherwise inwx will delete the not requested record type
-      dyndns_update_url="${DESEC_DYNDNS_UPDATE_URL}"
+      curl_parameters+=("--user" "$DYNB_USERNAME:$DYNB_PASSWORD")
-      ;;
+      curl_parameters+=("--get") # inwx will ignore the ipv6 parameter if you don't put it into the url
-    dynv6*)
+      dyndns_update_url="https://dyndns.inwx.com/nic/update"
-      dyndns_update_url="${DYNV6_DYNDNS_UPDATE_URL}"
+      provider_dns_servers=("ns.inwx.de" "ns2.inwx.de" "ns3.inwx.eu")
-      myip_str=ipv4
+    ;;
-      myipv6_str=ipv6
+    [Dd][Yy][Nn][Uu]*)
-      ;;
+      curl_parameters+=("--user" "$DYNB_USERNAME:$DYNB_PASSWORD")
-    DuckDNS* | duckdns*)
+      curl_parameters+=("--get")
-      dyndns_update_url="${DUCKDNS_DYNDNS_UPDATE_URL}"
+      dyndns_update_url="https://api.dynu.com/nic/update"
-      myip_str=ip
+      provider_dns_servers=("NS11.dynu.com" "NS10.dynu.com" "NS12.dynu.com")
-      myipv6_str=ipv6
+    ;;
-      ;;
+    [Dd][Ee][Ss][Ee][Cc]* | [Dd][Ee][Dd][Yy][Nn]* )
-    ddnss*)
+    # deSEC.de / dedyn.io
-      dyndns_update_url="${DDNSS_DYNDNS_UPDATE_URL}"
+      curl_parameters+=("--header" "Authorization: Token $DYNB_TOKEN")
-      ## we are currently not using the syntax with ip auto detection
+      curl_parameters+=("--get")
-      myip_str=ip
+      curl_parameters+=("--data-urlencode" "hostname=$DYNB_DYN_DOMAIN")
-      myipv6_str=ip6
+      dyndns_update_url="https://update.dedyn.io"
-      ;;
+      provider_dns_servers=("ns1.desec.io" "ns2.desec.org")
+      _provider_check_ip="https://checkip.dedyn.io" # checkipv4 and checkipv6 is also available
+    ;;
+    [Dd][Yy][Nn][Vv]6*)
+    # dynv6.com
+      ipv4_parameter_name=ipv4
+      ipv6_parameter_name=ipv6
+      curl_parameters+=("--get")
+      curl_parameters+=("--data-urlencode" "zone=$DYNB_DYN_DOMAIN")
+      curl_parameters+=("--data-urlencode" "token=$DYNB_TOKEN")
+      dyndns_update_url="https://dynv6.com/api/update"
+      provider_dns_servers=("ns1.dynv6.com" "ns2.dynv6.com" "ns3.dynv6.com")
+    ;;
+    [Dd][Uu][Cc][Kk][Dd][Nn][Ss]*)
+    # DuckDNS.org
+      ipv4_parameter_name=ip
+      ipv6_parameter_name=ipv6
+      curl_parameters+=("--get")
+      curl_parameters+=("--data-urlencode" "domains=$DYNB_DYN_DOMAIN")
+      curl_parameters+=("--data-urlencode" "token=$DYNB_TOKEN")
+      dyndns_update_url="https://www.duckdns.org/update"
+      provider_dns_servers=("ns1.duckdns.org" "ns2.duckdns.org")
+    ;;
+    [Dd][Dd][Nn][Ss][Ss]*)
+    # ddnss.de
+      ipv4_parameter_name=ip
+      ipv6_parameter_name=ip6
+      curl_parameters+=("--get")
+      curl_parameters+=("--data-urlencode" "host=$DYNB_DYN_DOMAIN")
+      curl_parameters+=("--data-urlencode" "key=$DYNB_TOKEN")
+      dyndns_update_url="https://ddnss.de/upd.php"
+      provider_dns_servers=("ns1.ddnss.de" "ns2.ddnss.de" "ns3.ddnss.de")
+    ;;
     [Ii][Pp][Vv]64*)
-      dyndns_update_url="${IPV64NET_DYNDNS_UPDATE_URL}"
+    # IPv64.net
-      myip_str=ip
+      ipv4_parameter_name=ip
-      myipv6_str=ip6
+      ipv6_parameter_name=ip6
-      ;;
+      curl_parameters+=("--request" "POST")
+      curl_parameters+=("--header" "Authorization: Bearer $DYNB_TOKEN")
+      curl_parameters+=("--data-urlencode" "domain=$DYNB_DYN_DOMAIN")
+      dyndns_update_url="https://ipv64.net/nic/update"
+      provider_dns_servers=("ns1.IPv64.net" "ns2.IPv64.net")
+    ;;
     *)
       errorMessage "$DYNB_SERVICE_PROVIDER is not supported"
       exit 1
-      ;;
+    ;;
   esac
+  if test -n "$_DNS_checkServer"
+  then provider_dns_servers=("$_DNS_checkServer" "${provider_dns_servers[@]}")
+  fi
+}
+
+function prepare_ip_flag_parameters
+{
+  debugMessage "IPv4 enabled: $_is_IPv4_enabled; IPv6 enabled: $_is_IPv6_enabled; has remote IPv4: $_has_remote_ip4; has remote IPv6: $_has_remote_ip6"
+  if [[ $_is_IPv4_enabled == true ]] && [[ $_is_IPv6_enabled == true ]] && [[ $_has_remote_ip4 == true ]] && [[ $_has_remote_ip6 == true ]]
+  then
+    ip_flag_parameters=("--data-urlencode" "${ipv4_parameter_name}=${_remote_IPv4}" "--data-urlencode" "${ipv6_parameter_name}=${_remote_IPv6}")
+  fi
+  if [[ $_is_IPv4_enabled == true ]] && [[ $_is_IPv6_enabled == false ]] || [[ $_is_IPv4_enabled == true ]] && [[ $_is_IPv6_enabled == true ]] && [[ $_has_remote_ip4 == true ]] && [[ $_has_remote_ip6 == false ]]
+  then
+    ip_flag_parameters=("--data-urlencode" "${ipv4_parameter_name}=${_remote_IPv4}")
+  fi
+  if [[ $_is_IPv4_enabled == false ]] && [[ $_is_IPv6_enabled == true ]] || [[ $_is_IPv4_enabled == true ]] && [[ $_is_IPv6_enabled == true ]] && [[ $_has_remote_ip4 == false ]] && [[ $_has_remote_ip6 == true ]]
+  then
+    ip_flag_parameters=("--data-urlencode" "${ipv6_parameter_name}=${_remote_IPv6}")
+  fi
 }
 
 function send_request
 {
-    case $DYNB_SERVICE_PROVIDER in
+  local _response
-    inwx* | INWX*)
+  debugMessage "curl parameters: ${curl_parameters[*]} ${dyndns_update_url}"
-      _response=$(curl --silent "$_interface_str" \
+  _response=$(
-        --user-agent "$_userAgent" \
+    curl --silent "$_interface_str" \
-        --user "$DYNB_USERNAME":"$DYNB_PASSWORD" \
+    "${curl_parameters[@]}" \
-        "${dyndns_update_url}")
+    "${dyndns_update_url}")
-      analyse_response
+  _curl_exit_code=$?
-      status_code=$?
+  analyse_response
-      ;;
+  status_code=$?
-    deSEC* | desec* | dedyn*)
-      _response=$(curl --silent "$_interface_str" \
-        --user-agent "$_userAgent" \
-        --header "Authorization: Token $DYNB_TOKEN" \
-        --get --data-urlencode "hostname=$DYNB_DYN_DOMAIN" \
-        "${dyndns_update_url}")
-      analyse_response
-      status_code=$?
-      ;;
-    [Ii][Pp][Vv]64* )
-      _response=$(curl --silent "$_interface_str" \
-        --user-agent "$_userAgent" \
-        --header "Authorization: Bearer $DYNB_TOKEN" \
-        --request POST \
-        --form "domain=$DYNB_DYN_DOMAIN" \
-        "${dyndns_update_url}")
-      analyse_response
-      status_code=$?
-    ;;
-    dynv6* | duckDNS* | duckdns* | ddnss*)
-      _response=$(
-        curl --silent "$_interface_str" \
-          --user-agent "$_userAgent" \
-          "${dyndns_update_url}")
-      analyse_response
-      status_code=$?
-      ;;
-  esac
   return $status_code
 }
 
@@ -366,7 +527,7 @@ function analyse_response
       debugMessage "Response: $_response"
       return 1
       ;;
-    *'Bad Request'*)
+    400* | *'Bad Request'*)
       errorMessage "Bad Request."
       debugMessage "Response: $_response"
       return 1
@@ -416,12 +577,16 @@ function analyse_response
       errorMessage "$_response: There is an internal error in the dyndns update system. Retry update no sooner than 30 minutes."
       return 1
       ;;
-    911 | 5*)
+    servererror | 911 | 5*)
       errorMessage "$_response: A fatal error on provider side such as a database outage. Retry update no sooner than 30 minutes."
       return 1
       ;;
     *)
-      if [[ "$_response" == "$_status" ]]; then
+      if test $_curl_exit_code -gt 0
+      then
+        analyse_curl_exit_code $_curl_exit_code
+        return $?  
+      elif test -n "$_response" && [[ "$_response" == "$_previous_response_was" ]]; then
         errorMessage "An unknown response code has been received: $_response"
         return 1
       else
@@ -432,45 +597,57 @@ function analyse_response
   esac
 }
 
+function analyse_curl_exit_code
+{
+  local current_curl_exit_code=$1
+  case $current_curl_exit_code in
+    6)
+      errorMessage "curl exit code: $_curl_exit_code; Couldn't resolve host: $dyndns_update_url"
+    ;;
+    7)
+      errorMessage "curl exit code: $_curl_exit_code; Failed to connect to host: $dyndns_update_url"
+    ;;
+    22)
+      errorMessage "curl exit code: $_curl_exit_code HTTP error code being 400 or above"
+    ;;
+    *)
+      errorMessage "curl exit code: $_curl_exit_code"
+    ;;
+  esac
+  return "$current_curl_exit_code"
+}
+
 # using DynDNS2 protocol
 function dynupdate
 {
-  select_update_base_url
+  prepare_ip_flag_parameters
-
+  curl_parameters+=("${ip_flag_parameters[@]}")
-  # pre encode ip parameters
+  send_request
-  if [[ $_is_IPv4_enabled == true ]] && [[ $_is_IPv6_enabled == true ]]
+  request_status=$?
-  then
-    dyndns_update_url="${dyndns_update_url}${myip_str}=${_new_IPv4}&${myipv6_str}=${_new_IPv6}"
-    send_request
-    request_status=$?
-  fi
-  if [[ $_is_IPv4_enabled == true ]] && [[ $_is_IPv6_enabled == false ]]
-  then
-    dyndns_update_url="${dyndns_update_url}${myip_str}=${_new_IPv4}"
-    send_request
-    request_status=$?
-  fi
-  if [[ $_is_IPv4_enabled == false ]] && [[ $_is_IPv6_enabled == true ]]
-  then
-    dyndns_update_url="${dyndns_update_url}${myipv6_str}=${_new_IPv6}"
-    send_request
-    request_status=$?
-  fi
-  debugMessage "Update URL was: $dyndns_update_url"
   return $request_status
 }
 
 function setStatus
 {
-  echo "_status=$1; _eventTime=$2; _errorCounter=$3; _statusHostname=$4; _statusUsername=$5; _statusPassword=$6" >/tmp/dynb.status
+  echo "_curl_exit_code_was=$1; _previous_response_was=$2 _eventTime=$3; _errorCounter=$4; _statusHostname=$5; _statusUsername=$6; _statusPassword=$7" >/tmp/dynb.status
 }
 
+declare _previous_response_was
+declare _curl_exit_code_was
+
 # handle errors from past update requests
 function checkStatus
 {
-  case $_status in
+  local check_string
+  if [[ -z "${_previous_response_was}" ]]
+  then check_string=$_curl_exit_code_was
+  else check_string=$_previous_response_was
+  fi
+  
+  case $check_string in
     *nochg*)
-      if [[ _errorCounter -gt 1 ]]; then
+      if [[ _errorCounter -gt 1 ]]
+      then
         errorMessage "The update client was spamming unnecessary update requests, something might be wrong with your IP-Check site."
         errorMessage "Fix your config and then delete $_statusFile or restart your docker container"
         return 1
@@ -480,7 +657,7 @@ function checkStatus
       if [[ "$_statusHostname" == "$DYNB_DYN_DOMAIN" && ("$_statusUsername" == "$DYNB_USERNAME" || $_statusUsername == "$DYNB_TOKEN") ]]; then
         errorMessage "Hostname supplied does not exist under specified account, enter new login credentials before performing an additional request."
         return 1
-      else rm "$_statusFile"
+      else delete_status_file
       fi
       return 0
       ;;
@@ -488,7 +665,7 @@ function checkStatus
       if [[ "$_statusUsername" == "$DYNB_USERNAME" &&  ("$_statusPassword" == "$DYNB_PASSWORD" || $_statusPassword == "$DYNB_TOKEN") ]]; then
         errorMessage "Invalid username password combination."
         return 1
-      else rm "$_statusFile"
+      else delete_status_file
       fi
       return 0
       ;;
@@ -509,102 +686,88 @@ function checkStatus
       echo "If it still fails file an issue at github or try another client :)"
       return 1
       ;;
-    911 | 5* | *'Too Many Requests'*)
+    servererror | 911 | 5* | *'Too Many Requests'*)
-      delta=$(($(date +%s) - _eventTime))
+      if check_delay 30
-      if [[ $delta -lt 1800 ]]
       then
-        errorMessage "$_status: The provider currently has an fatal error. DynB will wait for next update until 30 minutes have passed since last request, $(date --date=@$delta -u +%M) minutes already passed."
+        delete_status_file
+        return 0
+      else
+        errorMessage "$_previous_response_was: The provider currently has a fatal error."
         return 1
-      else rm "$_statusFile"
       fi
-      return 0
       ;;
     *'Bad Request'*)
-      if [[ "$_statusUsername" == "$DYNB_USERNAME" &&  ("$_statusPassword" == "$DYNB_PASSWORD" || $_statusPassword == "$DYNB_TOKEN") ]]; then
+      if [[ "$_statusUsername" == "$DYNB_USERNAME" &&  ("$_statusPassword" == "$DYNB_PASSWORD" || $_statusPassword == "$DYNB_TOKEN") ]]
+      then
         errorMessage "Bad Request: Please check your credentials, maybe your token is invalid."
         return 1
-      else rm "$_statusFile"
+      else delete_status_file
       fi
       return 0
       ;;
     *)
-      if [[ _errorCounter -gt 1 ]]
+      if [[ $_errorCounter -gt 1 ]] && [[ "$_curl_exit_code_was" -eq 0 ]]
       then
         errorMessage "An unknown response code has repeatedly been received. $_response"
         return 1
+      elif [[ $_errorCounter -gt 1 ]] && [[ "$_curl_exit_code_was" -eq 7 ]]
+      then
+        if check_delay 15
+        then
+          delete_status_file
+          return 0
+        else return 1
+        fi
       else return 0
       fi
       ;;
   esac
 }
 
+function check_delay
+{
+  local minutes=$1
+  local seconds=$(( minutes * 60 ))
+  delta=$(($(date +%s) - _eventTime))
+  if [[ $delta -lt $seconds ]]
+  then
+    errorMessage "DynB only executes an update when $minutes minutes have passed since the last failed request, $(date --date=@$delta -u +%M) minutes have already passed."
+    if loopMode
+    then sleep $seconds
+    else return 1
+    fi
+  else return 0
+  fi
+}
+
 # requires parameter
 # 1. param: 4 or 6 for IP version
 function ipHasChanged
 {
   local ip_version=$1
+  getRemoteIP "$ip_version"
+  if test $? -gt 0
+  then return 1
+  fi
   case ${ip_version} in
     4)
-      remote_ip=$(getRemoteIP 4 $_ipv4_checker)
+      getDNSIP A
-      if ! is_IPv4_address "$remote_ip"
+      _remote_IPv4=$_remote_ip
-      then
+      debugMessage "IPv4 from remote IP check server: $_remote_IPv4, IPv4 from DNS: $_dns_ip"
-        errorMessage "The response from the IP check server is not an IPv4 address: $remote_ip"
+    ;;
-        return 1
-      fi
-      if [[ $DYNB_UPDATE_METHOD == domrobot ]]
-      then dns_ip=$(getDNSIP A)
-      else
-        if [[ -n $_DNS_checkServer ]]
-        then dig_response=$(dig @"${_DNS_checkServer}" in a +short "$DYNB_DYN_DOMAIN")
-        else dig_response=$(dig in a +short "$DYNB_DYN_DOMAIN")
-        fi
-        if [[ $dig_response == ";; connection timed out; no servers could be reached" ]]
-        then
-          errorMessage "DNS request failed $dig_response"
-          return 1
-        fi
-        # If the dns resolver lists multiple records in the answer section we filter the first line
-        # using short option "-n" and not "--lines" because of alpines limited BusyBox head command
-        dns_ip=$(echo "$dig_response" | head -n 1)
-      fi
-      _new_IPv4=$remote_ip
-      debugMessage "IPv4 from remote IP check server: $_new_IPv4, IPv4 from DNS: $dns_ip"
-      ;;
     6)
-      remote_ip=$(getRemoteIP 6 $_ipv6_checker)
+      getDNSIP AAAA
-      if ! is_IPv6_address "$remote_ip"
+      _remote_IPv6=$_remote_ip
-      then
+      debugMessage "IPv6 from remote IP check server: $_remote_IPv6, IPv6 from DNS: $_dns_ip"
-        errorMessage "The response from the IP check server is not an IPv6 address: $remote_ip"
+    ;;
-        return 1
-      fi
-      if [[ $DYNB_UPDATE_METHOD == domrobot ]]
-      then dns_ip=$(getDNSIP AAAA)
-      else
-        if [[ -n $_DNS_checkServer ]]
-        then dig_response=$(dig @"${_DNS_checkServer}" in aaaa +short "$DYNB_DYN_DOMAIN")
-        else dig_response=$(dig in aaaa +short "$DYNB_DYN_DOMAIN")
-        fi
-        exitcode=$?
-        if [[ $exitcode -gt 0 ]]
-        then
-          errorMessage "DNS request failed with exit code: $exitcode $dig_response"
-          return 1
-        fi
-        # If the dns server lists multiple records in the answer section we filter the first line
-        dns_ip=$(echo "$dig_response" | head -n 1)
-      fi
-      _new_IPv6=$remote_ip
-      debugMessage "IPv6 from remote IP check server: $_new_IPv6, IPv6 from DNS: $dns_ip"
-      ;;
-    *) ;;
   esac
 
-  if [[ "$remote_ip" == "$dns_ip" ]]
+  if [[ "$_remote_ip" == "$_dns_ip" ]]
   then return 1
   else
     case ${ip_version} in
-    4) infoMessage "New IPv4: $_new_IPv4 old was: $dns_ip";;
+    4) infoMessage "Remote IPv4: $_remote_IPv4 DNS IPv4: $_dns_ip";;
-    6) infoMessage "New IPv6: $_new_IPv6 old was: $dns_ip";;
+    6) infoMessage "Remote IPv6: $_remote_IPv6 DNS IPv6: $_dns_ip";;
     esac
     return 0
   fi
@@ -626,7 +789,7 @@ function handleParameters
   fi
   # shellcheck disable=SC2154
   if [[ $_arg_debug == "on" ]] || [[ $DYNB_DEBUG == true ]]
-  then _debug=1
+  then _debug=true
   fi
   # shellcheck disable=SC2154
   if [[ $_arg_update_method != "" ]]
@@ -666,8 +829,8 @@ function handleParameters
   elif [[ $DYNB_INTERVAL -lt _minimum_looptime ]]
   then
     DYNB_INTERVAL=$_minimum_looptime
-    _loopMode=1
+    _loopMode=true
-  else _loopMode=1
+  else _loopMode=true
   fi
   if [[ $_network_interface != "" ]]
   then _interface_str="--interface $_network_interface"
@@ -734,8 +897,8 @@ function doUnsets
   unset _is_IPv4_enabled
   unset _is_IPv6_enabled
   unset _main_domain
-  unset _new_IPv4
+  unset _remote_IPv4
-  unset _new_IPv6
+  unset _remote_IPv6
   unset _version
   unset DYNB_DYN_DOMAIN
   unset DYNB_USERNAME
@@ -776,11 +939,19 @@ function delete_status_file
   then
     debugMessage "Delete status file with previous errors"
     rm "$_statusFile"
+    unset _curl_exit_code_was
+    unset _previous_response_was
+    unset _eventTime
+    unset _errorCounter
+    unset _statusHostname
+    unset _statusUsername
+    unset _statusPassword
   fi
 }
 
 function doDynDNS2Updates
 {
+  prepare_request_parameters
   changed=0
   if [[ $_is_IPv4_enabled == true ]] && ipHasChanged 4
   then ((changed += 1))
@@ -799,11 +970,11 @@ function doDynDNS2Updates
         delete_status_file
       else
         debugMessage "Save new status after dynupdate has failed"
-        setStatus "$_response" "$(date +%s)" $((_errorCounter += 1)) "$DYNB_DYN_DOMAIN" "${DYNB_USERNAME}" "${DYNB_PASSWORD}${DYNB_TOKEN}"
+        setStatus "$_curl_exit_code" "$_response" "$(date +%s)" $((_errorCounter += 1)) "$DYNB_DYN_DOMAIN" "${DYNB_USERNAME}" "${DYNB_PASSWORD}${DYNB_TOKEN}"
       fi
     else debugMessage "Skip DynDNS2 update, checkStatus fetched previous error."
     fi
-  else debugMessage "Skip DynDNS2 update, IPs are up to date."
+  else debugMessage "Skip DynDNS2 update"
   fi
 }
 
@@ -818,17 +989,20 @@ function doUpdates
 
 function ipv6_is_not_working
 {
-  curl --ipv6 --head --silent --max-time 5 $_internet_connectivity_test_server > /dev/null
+  execute_connectivity_check 6
-  status_code=$?
+  return $?
-  if test $status_code -gt 0
-  then return 0
-  else return 1
-  fi
 }
 
 function ipv4_is_not_working
 {
-  curl --ipv4 --head --silent --max-time 5 $_internet_connectivity_test_server > /dev/null
+  execute_connectivity_check 4
+  return $?
+}
+
+function execute_connectivity_check
+{
+  local ip_version=$1
+  curl --ipv"$ip_version" --head --silent --max-time 5 $_internet_connectivity_test_server > /dev/null
   status_code=$?
   if test $status_code -gt 0
   then return 0
@@ -898,7 +1072,7 @@ function main
     do
       doUpdates
       debugMessage "wait $DYNB_INTERVAL seconds until next check"
-      sleep $DYNB_INTERVAL
+      sleep "$DYNB_INTERVAL"
     done
   else doUpdates
   fi