Choose an IP address family for outgoing requests

Useful where remote endpoints filter requests by IP address, but one's
Internet connection has a stable IP for only one address family,
e.g.: a dynamic IPv6 prefix and a static IPv4 address; or a static IPv6
prefix and CGNAT IPv4.

acme.sh

@@ -1897,6 +1897,11 @@ _inithttp() {
 
   if [ -z "$_ACME_CURL" ] && _exists "curl"; then
     _ACME_CURL="curl --silent --dump-header $HTTP_HEADER "
+    if [ "$ACME_USE_IPV6_REQUESTS" ]; then
+      _ACME_CURL="$_ACME_CURL --ipv6 "
+    elif [ "$ACME_USE_IPV4_REQUESTS" ]; then
+      _ACME_CURL="$_ACME_CURL --ipv4 "
+    fi
     if [ -z "$ACME_HTTP_NO_REDIRECTS" ]; then
       _ACME_CURL="$_ACME_CURL -L "
     fi
@@ -1924,6 +1929,11 @@ _inithttp() {
 
   if [ -z "$_ACME_WGET" ] && _exists "wget"; then
     _ACME_WGET="wget -q"
+    if [ "$ACME_USE_IPV6_REQUESTS" ]; then
+      _ACME_WGET="$_ACME_WGET --inet6-only "
+    elif [ "$ACME_USE_IPV4_REQUESTS" ]; then
+      _ACME_WGET="$_ACME_WGET --inet4-only "
+    fi
     if [ "$ACME_HTTP_NO_REDIRECTS" ]; then
       _ACME_WGET="$_ACME_WGET --max-redirect 0 "
     fi
@@ -7076,6 +7086,8 @@ Parameters:
   --alpn                            Use standalone alpn mode.
   --stateless                       Use stateless mode.
                                       See: $_STATELESS_WIKI
+  --request-v4                      Force client requests to use ipv4.
+  --request-v6                      Force client requests to use ipv6.
 
   --apache                          Use Apache mode.
   --dns [dns_hook]                  Use dns manual mode or dns api. Defaults to manual mode when argument is omitted.
@@ -7255,6 +7267,20 @@ _processAccountConf() {
     _saveaccountconf "ACME_USE_WGET" "$ACME_USE_WGET"
   fi
 
+  if [ "$_request_v6" ]; then
+    _saveaccountconf "ACME_USE_IPV6_REQUESTS" "$_request_v6"
+    _clearaccountconf "ACME_USE_IPV4_REQUESTS"
+  elif [ "$ACME_USE_IPV6_REQUESTS" ]; then
+    _saveaccountconf "ACME_USE_IPV6_REQUESTS" "$ACME_USE_IPV6_REQUESTS"
+    _clearaccountconf "ACME_USE_IPV4_REQUESTS"
+  elif [ "$_request_v4" ]; then
+    _saveaccountconf "ACME_USE_IPV4_REQUESTS" "$_request_v4"
+    _clearaccountconf "ACME_USE_IPV6_REQUESTS"
+  elif [ "$ACME_USE_IPV4_REQUESTS" ]; then
+    _saveaccountconf "ACME_USE_IPV4_REQUESTS" "$ACME_USE_IPV4_REQUESTS"
+    _clearaccountconf "ACME_USE_IPV6_REQUESTS"
+  fi
+
 }
 
 _checkSudo() {
@@ -7420,6 +7446,8 @@ _process() {
   _local_address=""
   _log_level=""
   _auto_upgrade=""
+  _request_v4=""
+  _request_v6=""
   _listen_v4=""
   _listen_v6=""
   _openssl_bin=""
@@ -7885,6 +7913,18 @@ _process() {
       fi
       AUTO_UPGRADE="$_auto_upgrade"
       ;;
+    --request-v4)
+      _request_v4="1"
+      ACME_USE_IPV4_REQUESTS="1"
+      _request_v6=""
+      ACME_USE_IPV6_REQUESTS=""
+      ;;
+    --request-v6)
+      _request_v6="1"
+      ACME_USE_IPV6_REQUESTS="1"
+      _request_v4=""
+      ACME_USE_IPV4_REQUESTS=""
+      ;;
     --listen-v4)
       _listen_v4="1"
       Le_Listen_V4="$_listen_v4"