Commit 6402f68e authored by Thomas Markwalder's avatar Thomas Markwalder Committed by Tomek Mrugalski
Browse files

[5680] User guide updated with new params

    Added discussion of new params to Dhcp4/dhcp-ddns section

    fixed missing params doxygen error
parent 1825ead4
......@@ -2579,9 +2579,16 @@ It is merely echoed by the server
<command>"replace-client-name": "never"</command>
<command>"generated-prefix": "myhost"</command>
<command>"hostname-char-set": ""</command>
<command>"hostname-char-replacement": ""</command>
......@@ -2908,6 +2915,50 @@ It is merely echoed by the server
<section xml:id="host-name-sanitization">
<title>Sanitizing Client host names</title>
It may be that some of your DHCP clients provide values in the Host Name
option (Option code 12), that contain undesirable characters. It is possible
to configure kea-dhcp4 to sanitize these values. The most typical use case
would be ensuring that only characters that are permitted by RFC 1035 be included:
A-Z,a-z,0-9, and '-'.
This may be accomplished with following two parameters:
<command>hostname-char-set</command> - a regular expression describing the
invalid character set. This can be any valid, regular expression using
POSIX extended expression syntax. For example, "[^A-Za-z0-9-]" would
replace any character other then the letters A through Z, a through, digits 0
through 9, and '-'. If your clients include domain names, you will need to make
sure that the dot, '.', is included the your expression: "[^A-Za-z0-9.-]".
The default value is an empty string and disables sanitization.
<command>hostname-char-replacement</command> - a string of zero or more characters
with which to replace each invalid character in the host name. The default value
is an empty string and will cause invalid characters to be OMITTED rather than
The following configuration, will replace anything other than a letter, digit,
hyphen, or dot with the letter 'x':
"Dhcp4": {
"dhcp-ddns": {
"hostname-char-set": "[^A-Za-z0-9.-]",
"hostname-char-replacement": "x",
Thus, a client supplied value of "myhost-$[" would become ""
Note that sanitization is peformed only on the portion of the name supplied by the
Host Name option, and that this is done before applying the qualifying suffix (if
one is defined).
<section xml:id="dhcp4-next-server">
......@@ -99,6 +99,10 @@ public:
/// supplied by the client with a generated name.
/// @param generated_prefix Prefix to use when generating domain-names.
/// @param qualifying_suffix Suffix to use to qualify partial domain-names.
/// @param hostname_char_set regular expression string which describes invalid
/// characters to be scrubbed from client host names
/// @param hostname_char_replacement string of zero or more characters to
/// replace invalid chars when sanitizing client host names
/// @c enable_updates is mandatory, @c qualifying_suffix is mandatory
/// when updates are enabled, other parameters are optional.
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