diff --git a/doc/guide/dhcp4-srv.xml b/doc/guide/dhcp4-srv.xml
index 313f50f253..6a636ae256 100644
--- a/doc/guide/dhcp4-srv.xml
+++ b/doc/guide/dhcp4-srv.xml
@@ -42,17 +42,17 @@
             ports other than the standard ones will not be able to
             handle regular DHCPv4 queries.</simpara>
           </listitem>
-	  <listitem>
+          <listitem>
             <simpara>
             <command>-t <replaceable>file</replaceable></command> -
             specifies the configuration file to be tested. Kea-dhcp4
-	    will attempt to load it, and will conduct sanity
-	    checks. Note that certain checks are possible only while
-	    running the actual server. The actual status is reported
-	    with exit code (0 = configuration looks ok, 1 = error
-	    encountered). Kea will print out log messages to standard
-	    output and error to standard error when testing
-	    configuration.</simpara>
+            will attempt to load it, and will conduct sanity
+            checks. Note that certain checks are possible only while
+            running the actual server. The actual status is reported
+            with exit code (0 = configuration looks ok, 1 = error
+            encountered). Kea will print out log messages to standard
+            output and error to standard error when testing
+            configuration.</simpara>
           </listitem>
           <listitem>
             <simpara>
diff --git a/doc/guide/dhcp6-srv.xml b/doc/guide/dhcp6-srv.xml
index fd6c4f714a..37e9209d10 100644
--- a/doc/guide/dhcp6-srv.xml
+++ b/doc/guide/dhcp6-srv.xml
@@ -42,17 +42,17 @@
             ports other than the standard ones will not be able to
             handle regular DHCPv6 queries.</simpara>
           </listitem>
-	  <listitem>
+          <listitem>
             <simpara>
             <command>-t <replaceable>file</replaceable></command> -
             specifies the configuration file to be tested. Kea-dhcp6
-	    will attempt to load it, and will conduct sanity
-	    checks. Note that certain checks are possible only while
-	    running the actual server. The actual status is reported
-	    with exit code (0 = configuration looks ok, 1 = error
-	    encountered). Kea will print out log messages to standard
-	    output and error to standard error when testing
-	    configuration.</simpara>
+            will attempt to load it, and will conduct sanity
+            checks. Note that certain checks are possible only while
+            running the actual server. The actual status is reported
+            with exit code (0 = configuration looks ok, 1 = error
+            encountered). Kea will print out log messages to standard
+            output and error to standard error when testing
+            configuration.</simpara>
           </listitem>
           <listitem>
             <simpara>