diff --git a/lib/resty/auto-ssl/ssl_certificate.lua b/lib/resty/auto-ssl/ssl_certificate.lua
index 70d3a78..9ccbd53 100644
--- a/lib/resty/auto-ssl/ssl_certificate.lua
+++ b/lib/resty/auto-ssl/ssl_certificate.lua
@@ -56,6 +56,8 @@ local function issue_cert_unlock(domain, storage, local_lock, distributed_lock_v
 end
 
 local function issue_cert(auto_ssl_instance, storage, domain)
+  local fullchain_pem, privkey_pem, err
+  local multiname = auto_ssl_instance:get("multiname_cert")
   -- Before issuing a cert, create a local lock to ensure multiple workers
   -- don't simultaneously try to register the same cert.
   local local_lock, new_local_lock_err = lock:new("auto_ssl", { exptime = 30, timeout = 30 })
@@ -90,7 +92,15 @@ local function issue_cert(auto_ssl_instance, storage, domain)
     issue_cert_unlock(domain, storage, local_lock, distributed_lock_value)
     return cert
   end
-
+  
+  if not multiname then
+    fullchain_pem, privkey_pem = storage:get_cert(domain)
+    if fullchain_pem and privkey_pem then
+      issue_cert_unlock(domain, storage, local_lock, distributed_lock_value)
+      return fullchain_pem, privkey_pem
+    end
+  end
+  
   ngx.log(ngx.NOTICE, "auto-ssl: issuing new certificate for ", domain)
   cert, err = ssl_provider.issue_cert(auto_ssl_instance, domain)
   if err then
@@ -277,6 +287,35 @@ local function do_ssl(auto_ssl_instance, ssl_options)
     return
   end
 
+  -- Check to ensure the domain is one we allow for handling SSL.
+  local allow_domain = auto_ssl_instance:get("allow_domain")
+  if not allow_domain(domain) then
+    ngx.log(ngx.NOTICE, "auto-ssl: domain not allowed - using fallback - ", domain)
+    return
+  end
+
+  local multiname = auto_ssl_instance:get("multiname_cert")
+  if multiname then
+    local storage = auto_ssl_instance:get("storage")
+    domain, sub_domain = storage:get_domains(domain, multiname)
+    local check_subdomain, size = storage:check_subdomain(domain, sub_domain)
+    if size then
+      if size>99 then
+        storage:set_subdomain(domain, sub_domain, sub_domain)
+        storage:set_subdomain(sub_domain, sub_domain)
+      elseif not check_subdomain then
+        storage:set_subdomain(domain, sub_domain, nil)
+        issue_cert(auto_ssl_instance, storage, domain)
+      end
+    elseif not check_subdomain then
+      storage:set_subdomain(domain, sub_domain, nil)
+      issue_cert(auto_ssl_instance, storage, domain)
+    end
+
+    local check_subdomain, size = storage:check_subdomain(domain, sub_domain)
+    domain = check_subdomain
+  end
+
   -- Get or issue the certificate for this domain.
   local cert_der, get_cert_der_err = get_cert_der(auto_ssl_instance, domain, ssl_options)
   if get_cert_der_err then
@@ -304,4 +343,4 @@ return function(auto_ssl_instance, ssl_options)
   if not ok then
     ngx.log(ngx.ERR, "auto-ssl: failed to run do_ssl: ", err)
   end
-end
+end
\ No newline at end of file
diff --git a/lib/resty/auto-ssl/ssl_providers/lets_encrypt.lua b/lib/resty/auto-ssl/ssl_providers/lets_encrypt.lua
index 680b94a..6048db2 100644
--- a/lib/resty/auto-ssl/ssl_providers/lets_encrypt.lua
+++ b/lib/resty/auto-ssl/ssl_providers/lets_encrypt.lua
@@ -11,6 +11,10 @@ function _M.issue_cert(auto_ssl_instance, domain)
   local base_dir = auto_ssl_instance:get("dir")
   assert(type(base_dir) == "string", "dir must be a string")
 
+  local hook_port = auto_ssl_instance:get("hook_server_port")
+  local multiname = auto_ssl_instance:get("multiname_cert")
+  domains = "--domain " .. domain .. " "
+
   local hook_port = auto_ssl_instance:get("hook_server_port")
   assert(type(hook_port) == "number", "hook_port must be a number")
   assert(hook_port <= 65535, "hook_port must be below 65536")
@@ -18,6 +22,19 @@ function _M.issue_cert(auto_ssl_instance, domain)
   local hook_secret = ngx.shared.auto_ssl_settings:get("hook_server:secret")
   assert(type(hook_secret) == "string", "hook_server:secret must be a string")
 
+  if multiname then
+    local storage = auto_ssl_instance:get("storage")
+    domain_list, size = storage:get_subdomain(domain)
+    domains = " "
+    if domain_list then
+      for _, i in pairs(domain_list) do
+        domains = domains .. "--domain " .. i .. " "
+      end
+    else
+      domains = "--domain " .. domain .. " "
+    end
+  end
+
   -- Run dehydrated for this domain, using our custom hooks to handle the
   -- domain validation and the issued certificates.
   --
@@ -31,7 +48,7 @@ function _M.issue_cert(auto_ssl_instance, domain)
     "--cron",
     "--accept-terms",
     "--no-lock",
-    "--domain", domain,
+    domains,
     "--challenge", "http-01",
     "--config", base_dir .. "/letsencrypt/config",
     "--hook", lua_root .. "/bin/resty-auto-ssl/letsencrypt_hooks",
@@ -93,4 +110,4 @@ function _M.issue_cert(auto_ssl_instance, domain)
   return cert
 end
 
-return _M
+return _M
\ No newline at end of file
diff --git a/lib/resty/auto-ssl/storage.lua b/lib/resty/auto-ssl/storage.lua
index 0f18f35..cabe119 100644
--- a/lib/resty/auto-ssl/storage.lua
+++ b/lib/resty/auto-ssl/storage.lua
@@ -1,8 +1,10 @@
 local resty_random = require "resty.random"
 local str = require "resty.string"
+local cjson = require "cjson"
 
 local _M = {}
 
+
 function _M.new(options)
   assert(options)
   assert(options["adapter"])
@@ -11,6 +13,180 @@ function _M.new(options)
   return setmetatable(options, { __index = _M })
 end
 
+function tablelength(a)
+  local count = 0
+  for _ in pairs(a) do count = count + 1 end
+  return count
+end
+
+function _M.get_domains(self, domain, level)
+    local function subdomain(a)
+      local x = {}
+      for word in string.gmatch(a, '([^.]+)') do
+          table.insert(x, word)
+      end
+      return x
+    end
+
+    local function get_name(name_list, size, level)
+      if level > size then
+        return nil
+      end
+      x = name_list[size]
+      for i=1, level-1 do
+        x = name_list[size-i] .. "." .. x
+      end
+      return x
+    end
+
+    if type(level) ~= "number" then
+      level = 2
+    end
+    local ar = subdomain(domain)
+    local size = tablelength(ar)
+
+    local main_domain = get_name(ar, size, level)
+    if main_domain then
+      return main_domain, domain
+    else
+      return domain, nil
+    end
+end
+
+function _M.get_subdomain(self, domain)
+    local function subdomains(a)
+      local x = {}
+      if a then
+        for word in string.gmatch(a, '([^:]+)') do
+          table.insert(x, word)
+        end
+        return x
+      end
+      return nil
+    end
+
+    local function check_max_len(subdomain_list, size)
+      local x = ((string.len(table.concat(subdomain_list, ":"))) * size) + (10 * size)
+      if x > 1000 then
+        return 100
+      else
+        return size
+      end
+    end
+
+    local json, err = self.adapter:get(domain .. ":main")
+    if err then
+       return nil, nil, err
+    elseif not json then
+       return nil
+    end
+    local data = cjson.decode(json)
+    local ar = subdomains(data['subdomain'])
+    local extended = subdomains(data['extended'])
+    local size = check_max_len(ar, tablelength(ar))
+    return ar, size, nil, extended
+end
+
+function _M.set_subdomain(self, domain, subdomain, extended)
+    local x, n, err, extended_list = self.get_subdomain(self, domain)
+
+    local function check_extended(extended, extended_list)
+      local x = nil
+      if extended_list then
+        x = table.concat(extended_list, ":") .. ":"
+      end
+      if extended then
+        if x then
+          x = x .. extended
+        else
+          x = extended
+        end
+      end
+      return x
+    end
+
+    local function set_subdomains(subdomain, subdomain_list, err, extend)
+      local function check_name(subdomain, subdomain_list)
+        for _, i in pairs(subdomain_list) do
+          if i == subdomain then
+            return true
+          end
+        end
+      end
+
+      if err then
+        return subdomain
+      end
+
+      local x = table.concat(subdomain_list, ":")
+      if check_name(subdomain, subdomain_list) then
+        return nil, true
+      elseif nil == string.find(x, subdomain) and extend then
+        return x
+      elseif nil == string.find(x, subdomain) then
+        x = x .. ":" .. subdomain
+        return x
+      end
+    end
+
+    local extend = check_extended(extended, extended_list)
+    local subdomain_list, exists = set_subdomains(subdomain, x, err,  extend)
+    if exists then
+      return
+    end
+    if extend then
+      data = cjson.encode({domain=domain,
+                           subdomain=subdomain_list,
+                           extended=extend})
+    else
+      data = cjson.encode({domain=domain,
+                           subdomain=subdomain_list})
+    end
+    self.adapter:set(domain .. ":main", data)
+end
+
+function _M.check_subdomain(self, domain, subdomain)
+  local x, n, err, extended = self.get_subdomain(self, domain)
+
+  local function check_main(domain_list, subdomain)
+    if domain_list then
+      local size = tablelength(domain_list)
+      for _, i in pairs(domain_list) do
+        if i == subdomain then
+          return domain, size
+        end
+      end
+    end
+  end
+
+  local function check_extended(self, extended_list, subdomain)
+    if extended_list then
+      for _, i in pairs(extended_list) do
+        domain, size = self.check_subdomain(self, i, subdomain)
+        if domain then
+          return domain, size
+        end
+      end
+    end
+  end
+
+  local domain, size = check_main(x, subdomain)
+  if domain then
+    return domain, size
+  end
+
+  local domain, size = check_extended(self, extended, subdomain)
+  if domain then
+    return domain, size
+  end
+
+  if n and n>99 then
+    return nil, n
+  end
+
+  return nil, nil
+end
+
 function _M.get_challenge(self, domain, path)
   return self.adapter:get(domain .. ":challenge:" .. path)
 end
@@ -132,4 +308,4 @@ function _M.issue_cert_unlock(self, domain, lock_rand_value)
   end
 end
 
-return _M
+return _M
\ No newline at end of file