diff --git a/src/bin/d2/d2_hooks.dox b/src/bin/d2/d2_hooks.dox
index e1bde28c57..8ef06a9b18 100644
--- a/src/bin/d2/d2_hooks.dox
+++ b/src/bin/d2/d2_hooks.dox
@@ -71,12 +71,11 @@ to the end of this list.
    - name: @b current_server, type: isc::d2::DnsServerInfoPtr, direction: <b>in</b>
    - name: @b tsig_key, type: isc::dns::TSIGKeyPtr, direction: <b>in/out</b>
 
- - @b Description: this callout is executed when the DNS server to send the
-   next DNS update was selected and a TSIG key to protect the DNS update
-   is looking for. Pointers to the selected DNS server and the current TSIG
-   key are provided. If a hook library wants to use another TSIG key the
-   pointer must be updated.
+ - @b Description: this callout is executed when the D2 is selecting for
+   a TSIG key to protect the next DNS update to the already chosen DNS
+   server. Pointers to the current DNS server and TSIG key are provided.
+   If a hook library wants to use another TSIG key the pointer must be updated.
 
- - <b>Next step status</b>: IF any callout sets the status to value different
-   from CONTINUE the selected server is skipped.
+ - <b>Next step status</b>: If any callout sets the status to a different
+   value than CONTINUE the current server is skipped.
 */
diff --git a/src/bin/d2/nc_trans.cc b/src/bin/d2/nc_trans.cc
index bca27aa70e..212cac1e9c 100644
--- a/src/bin/d2/nc_trans.cc
+++ b/src/bin/d2/nc_trans.cc
@@ -464,21 +464,21 @@ NameChangeTransaction::selectNextServer() {
     for (;;) {
         if ((current_server_list_) &&
             (next_server_pos_ < current_server_list_->size())) {
-            current_server_  = (*current_server_list_)[next_server_pos_];
+            current_server_ = (*current_server_list_)[next_server_pos_];
             // Toss out any previous response.
             dns_update_response_.reset();
 
-            // Set the tsig_key to that of the current server..
+            // Set the tsig_key to that of the current server.
             if (!selectTSIGKey()) {
                 ++next_server_pos_;
                 continue;
             }
 
-            // @todo  Protocol is set on DNSClient constructor.  We need
+            // @todo Protocol is set on DNSClient constructor. We need
             // to propagate a configuration value downward, probably starting
-            // at global, then domain, then server
+            // at global, then domain, finishing by server.
             // Once that is supported we need to add it here.
-            dns_client_.reset(new DNSClient(dns_update_response_ , this,
+            dns_client_.reset(new DNSClient(dns_update_response_, this,
                                             DNSClient::UDP));
             ++next_server_pos_;
             return (true);
@@ -507,7 +507,7 @@ NameChangeTransaction::selectTSIGKey() {
         HooksManager::callCallouts(Hooks.hooks_index_select_key_,
                                    *callout_handle);
 
-        // This server is skipped not NEXT_STEP_CONTINUE status.
+        // This server is skipped because of status is not NEXT_STEP_CONTINUE.
         if (callout_handle->getStatus() != CalloutHandle::NEXT_STEP_CONTINUE) {
             return (false);
         }
diff --git a/src/lib/d2srv/d2_config.h b/src/lib/d2srv/d2_config.h
index 9faf097f17..2017855033 100644
--- a/src/lib/d2srv/d2_config.h
+++ b/src/lib/d2srv/d2_config.h
@@ -451,21 +451,21 @@ public:
 
     /// @brief Getter which returns the server's hostname.
     ///
-    /// @return returns the hostname as as std::string.
+    /// @return the hostname as as std::string.
     const std::string getHostname() const {
         return (hostname_);
     }
 
     /// @brief Getter which returns the server's port number.
     ///
-    /// @return returns the port number as a unsigned integer.
+    /// @return the port number as a unsigned integer.
     uint32_t getPort() const {
         return (port_);
     }
 
     /// @brief Getter which returns the server's ip_address.
     ///
-    /// @return returns the address as an IOAddress reference.
+    /// @return the address as an IOAddress reference.
     const isc::asiolink::IOAddress& getIpAddress() const {
         return (ip_address_);
     }
@@ -473,7 +473,7 @@ public:
     /// @brief Convenience method which returns whether or not the
     /// server is enabled.
     ///
-    /// @return returns true if the server is enabled, false otherwise.
+    /// @return true if the server is enabled, false otherwise.
     bool isEnabled() const {
         return (enabled_);
     }
@@ -490,13 +490,13 @@ public:
 
     /// @brief Convenience method which returns the server's TSIG key name.
     ///
-    /// @return returns the key name in an std::string. If server has no
-    /// TSIG key, the string will empty.
+    /// @return the key name in an std::string. If server has no TSIG key,
+    /// the string will be empty.
     const std::string getKeyName() const;
 
-    /// @brief Getter which returns the server's TSIGKey info
+    /// @brief Getter which returns the server's TSIGKey info.
     ///
-    /// @return returns the pointer to the server storage.  If the server
+    /// @return the pointer to the server storage. If the server
     /// is not configured to use TSIG the pointer will be empty.
     const TSIGKeyInfoPtr& getTSIGKeyInfo() {
         return (tsig_key_info_);
@@ -581,7 +581,7 @@ public:
     /// @note: TSIG key infos are in servers.
     ///
     /// @return returns the key name in an std::string. If domain has no
-    /// TSIG key, the string will empty.
+    /// TSIG key, the string will be empty.
     const std::string getKeyName() const {
         return (key_name_);
     }