From 72d76f60293f49bdb243e315c7b0f8c2031e4c97 Mon Sep 17 00:00:00 2001
From: Zoran Pericic <zpericic@netst.org>
Date: Fri, 6 Nov 2015 00:41:56 +0100
Subject: [PATCH] Initial commit.

---
 dhclient-dnsupdate.sh |  11 ++
 dnsupdate             | 427 ++++++++++++++++++++++++++++++++++++++++++
 dnsupdate.cron        |   2 +
 dnsupdate.spec        |  63 +++++++
 ppp-dnsupdate.sh      |  10 +
 5 files changed, 513 insertions(+)
 create mode 100755 dhclient-dnsupdate.sh
 create mode 100755 dnsupdate
 create mode 100644 dnsupdate.cron
 create mode 100644 dnsupdate.spec
 create mode 100755 ppp-dnsupdate.sh

diff --git a/dhclient-dnsupdate.sh b/dhclient-dnsupdate.sh
new file mode 100755
index 0000000..0680b53
--- /dev/null
+++ b/dhclient-dnsupdate.sh
@@ -0,0 +1,11 @@
+#!/bin/bash
+
+dnsupdate_config() {
+    /usr/bin/dnsupdate "${interface}" "${new_ip_address}"
+    return 0
+}
+
+dnsupdate_restore() {
+    return 0
+}
+
diff --git a/dnsupdate b/dnsupdate
new file mode 100755
index 0000000..e922145
--- /dev/null
+++ b/dnsupdate
@@ -0,0 +1,427 @@
+#!/bin/bash
+# Dynamic DNS update script using ISC nsupdate 
+# Copyright (c) 2015 Zoran Pericic (zpericic@netst.org) all rights reserved.
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License, version 2,
+# as published by the Free Software Foundation.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software
+# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+#
+#
+# There is three type of options:
+#   DDNS_*
+#       - Global default if in /etc/sysconfig/network
+#       - First hostname options if in ifcfg- of conection.
+#       - Default for other hostnames.
+#   DDNS*_ (eg. DDNS0_HOSTNAME) - Where * is number starting from 0
+#       - Options for updating specific hostname.
+#       - DDNS*_HOSTNAME must be set to activate update.
+#   DDNS_PTR* - 
+#       - Options for updating PTR record.
+#       - Have all options except ZONE and REPLACE as DDNS*
+#
+# Valid variables are:
+# DDNS=yes|no
+#   Run Dynamic DNS update (default:yes if not public address).
+# DDNS_HOSTNAME
+#   Hostname to update. Defaults to DHCP_HOSTNAME, HOSTNAME and hostname.
+# DDNS*_HOSTNAME
+#   Hostname to update.
+# DDNS*_ZONE
+#   Zone to update (default: from hostname).
+# DDNS*_TTL
+#   Record TTL (default:300).
+# DDNS*_REPLACE
+#   Delete old records (default: yes).
+# DDNS*_SERVER
+#   Server to send updates (default: hostname zone SOA).
+# DDNS*_TCP
+#   Use TCP protocol for update (default: no, except for PTR).
+# DDNS*_GSS_TSIG=yes|no
+#   "no" to disable GSS-TSIG. Default authentification type if not tcp and other
+#   authentification is set and kinit runned succesfully. If not nsupdate is
+#   called without authentification.
+# DDNS*_GSS_KEYTAB="filename"
+#   Kerberos keytab filename with credential
+# DDNS*_GSS_PRINCIPAL="principal"
+#   GSS Principal (eg. 'host/example.com')
+# DDNS*_TSIG_FILE=filename
+#    Filename of key file which containing a named.conf-format key statement
+# DDNS*_TSIG_KEY_TYPE
+#    Name of the key algorithm (default: hmac-md5)
+# DDNS*_TSIG_KEY_NAME
+#    Key name
+# DDNS*_TSIG_KEY_SECRET
+#    Base64 encoded shared secret
+#
+# There is four way to authentificate:
+#   1. GSS-TSIG authentification (default)
+#       Set DDNS*_GSS_TSIG=yes or don't set any authenctification.
+#   2. TSIG authentification using file
+#       Set DDNS*_TSIG_FILE to key file.
+#   3. TSIG authentification with key
+#       Set DDNS*_TSIG_KEY_NAME and DDNS*_TSIG_KEY_SECRET and optionaly 
+#       DDNS*_TSIG_KEY_TYPE.
+#   4. No authentifiaction
+#       Used if DDNS*_GSS_TSIG=no or DDNS*_GSS_TSIG not set and keytab
+#       not found.
+#
+# Update PTR
+#
+# DDNS_PTR=yes|no
+#  "no" to disable update of PTR record (default: yes).
+# DDNS_PTR_HOSTNAME
+#   Hostname to use for PTR record. Defaults to DDNS_HOSTNAME.
+# DDNS_PTR_ZONE
+#   Not used. Constructed from IP adress.
+# DDNS_PTR_REPLACE
+#   Not used. Always yes.
+#
+# DDNS_PTR_TTL
+# DDNS_PTR_SERVER
+# DDNS_PTR_GSS_TSIG
+# DDNS_PTR_TSIG_FILE
+# DDNS_PTR_TSIG_KEY_TYPE
+# DDNS_PTR_TSIG_KEY_NAME
+# DDNS_PTR_TSIG_KEY_SECRET
+#   Same as DDNS*.
+#
+
+[ ! -x /usr/bin/nsupdate ] && exit 0;
+
+# Debugging is disabled by default
+DDNS_DEBUG=${DDNS_DEBUG:=no}
+
+function run_nsupdate() {
+	local rr_name=${1}
+	local ttl=${2}
+	local type=${3}
+	local rr_data=${4}
+	local replace=${5}
+	local server=${6}
+	local tcp=${7}
+	local zone=${8}
+	local gss_tsig=${9}
+	local gss_keytab=${10}
+	local gss_principal=${11}
+	local tsig_file=${12}
+	local tsig_key_type=${13}
+	local tsig_key_name=${14}
+	local tsig_key_secret=${15}
+	local cmd_server
+	local cmd_zone
+	local cmd_key
+	local cmd_replace
+	local cmd_params
+	local cc_file
+
+	[ -z "${rr_name}" ] && return 1
+	[ -z "${ttl}" ] && return 1
+	[ -z "${type}" ] && return 1
+	[ -z "${rr_data}" ] && return 1
+
+	[ -n "${server}" ] && cmd_server="server ${server}"
+	[ -n "${zone}" ] && cmd_zone="zone ${zone}"
+	[ "x${tcp}x" == "xyesx" ] && cmd_params="-v"
+
+	if [ "x${DDNS_DEBUG}x" != "xnox" ]; then
+#		cmd_params='-d'
+		echo "dnsupdate: updating: $rr_name $ttl IN $type $rr_data"
+		echo -e \
+"Params: \n" \
+"	RR Name:           \"${rr_name}\"\n" \
+"	TTL:               \"${ttl}\"\n" \
+"	Type:              \"${type}\"\n" \
+"	RR Data:           \"${rr_data}\"\n" \
+"	Replace:           \"${replace}\"\n" \
+"	Server:            \"${server}\"\n" \
+"	TCP:               \"${tcp}\"\n" \
+"	Zone:              \"${zone}\"\n" \
+"	GSS-TSIG:          \"${gss_tsig}\"\n" \
+"	GSS Keytab:        \"${gss_keytab}\"\n" \
+"	GSS Principal:     \"${gss_principal}\"\n" \
+"	TSIG File:         \"${tsig_file}\"\n" \
+"	TSIG Key type:     \"${tsig_key_type}\"\n" \
+"	TSIG Key name:     \"${tsig_key_name}\"\n" \
+"	TSIG Key secret:   \"${tsig_key_secret}\"\n"
+	fi
+
+	if [ -n "${tsig_file}" ]; then
+		[ -f "${tsig_file}" ] && logger -p daemon.info "TSIG keyfile not exists." && return 1;
+		cmd_params="${cmd_params} -k ${tsig_file}"
+	elif [ -n "${tsig_key_name}" ]  && [ -n "${tsig_key_secret}" ]; then
+		if [ -n "${tsig_key_type}" ]; then
+			cmd_key="${tsig_key_type}:"
+		fi
+		cmd_key="key ${cmd_key}${tsig_key_name} ${tsig_key_secret}"
+	fi
+
+	#
+	# Init kerberos credential cache if needed.
+	#
+	if [ "x${tsig_gss}x" == "xyesx" ] || [ "x${tcp}x" != "xyesx" ] && [ "x${tsig_gss}x" != "xnox" ] && [ -z "${tsig_file}" ] && [ -z "${cmd_key}" ]; then
+		cc_file=`mktemp`
+		if [ -n "${tsig_gss_keytab}" ] && [ -f "${tsig_gss_keytab}" ] && [ -n "${tsig_gss_principal}" ]; then
+			kinit -k ${tsig_gss_keytab} -c ${cc_file} ${tsig_gss_principal}
+			[ $? -ne 0 ] | logger -p daemon.info "dnsupdate: kinit (1) failed" | return 1
+			cmd_params="${cmd_params} -g"
+		elif [ -n "${tsig_gss_principal}" ]; then
+			kinit -k -c ${cc_file} ${tsig_gss_principal}
+			[ $? -ne 0 ] && logger -p daemon.info "dnsupdate: kinit (2) failed" | return 1
+			cmd_params="${cmd_params} -g"
+		else
+			kinit -k -c ${cc_file}
+			if [ $? -eq 0 ]; then
+				cmd_params="${cmd_params} -g"
+			else
+				[ "x${tsig_gss}x" == "xyesx" ] && logger -p daemon.info "dnsupdate: kinit (3) failed: ${cc_file}" | return 1
+			fi
+		fi
+	fi
+
+	# Should we replace record
+	if [ "x${replace}x" != "xnox" ]; then
+		cmd_replace=$(cat <<EOF
+${cmd_zone}
+${cmd_key}
+prereq yxrrset ${rr_name} IN ${type}
+update delete ${rr_name} IN ${type}
+send
+EOF
+)
+	fi
+
+	# Runing nsupdate
+	KRB5CCNAME="FILE:${cc_file}" /usr/bin/nsupdate ${cmd_params} >/dev/null 2>&1  <<EOF
+${cmd_server}
+${cmd_replace}
+${cmd_zone}
+${cmd_key}
+update add ${rr_name} ${ttl} IN ${type} ${rr_data}
+send
+EOF
+
+	if [ $? -eq 0 ]; then
+		logger -p daemon.info "dnsupdate: updating: $rr_name $ttl IN $type $rr_data: Successfully"
+		echo "dnsupdate: updating: $rr_name $ttl IN $type $rr_data: Successfully"
+	else
+		logger -p daemon.info "dnsupdate: updating: $rr_name $ttl IN $type $rr_data: Failed"
+		echo "dnsupdate: updating: $rr_name $ttl IN $type $rr_data: Failed"
+	fi
+
+	# Destroy kerberos credential cache
+	[ -f "${cc_file}" ] && kdestroy -c ${cc_file}
+
+	return 0
+}
+
+function check_ip() {
+	local ips=`nslookup $1 | awk '/^Address: / { print \$2 }'`
+	local count=`echo $ips | wc -l`
+
+	if [ "$3" == "yes" ]; then
+		[ "$count" -gt "1" ] && return 1
+		[ "$ips" == "$2" ] && return 1 || return 0
+	else
+		[[ $ips =~ $2 ]] && return 1 || return 0
+	fi
+}
+
+function parse_ddns_config() {
+	local rr_name
+	local ttl
+	local type
+	local rr_data
+	local replace
+	local server
+	local tcp
+	local zone
+	local gss_tsig
+	local gss_keytab
+	local gss_principal
+	local tsig_file
+	local tsig_key_type
+	local tsig_key_name
+	local tsig_key_secret
+	local hostnum=0
+	local default_hostname=${DHCP_HOSTNAME-${HOSTNAME-$(hostname)}}
+	local ip_address=${1}
+	local public_ip=no
+
+	[[ ! $ip_address =~ ^192\.168|10\.|172\.1[6789]\.|172\.2[0-9]\.|172\.3[01]\. ]] && public_ip=yes
+
+	[ $public_ip == "yes" ] && [ "${DDNS}" != "yes" ] && return 0
+
+	#
+	# Update $DDNS_HOSTNAME
+	#
+	if [ -n "${DDNS_HOSTNAME}" ] || [ -z "${DDNS0_HOSTNAME}" ] && [ -n "${DDNS_HOSTNAME-${default_hostname}}" ]; then
+		rr_name=${DDNS_HOSTNAME:-${default_hostname}}
+		ttl=${DDNS_TTL:-300}
+		type=${DDNS_TYPE:-A}
+		rr_data=$ip_address
+		replace=${DDNS_REPLACE:-yes}
+		server=${DDNS_SERVER}
+		tcp=${DDNS_TCP:-no}
+		zone=${DDNS_ZONE}
+		gss_tsig=${DDNS_GSS_TSIG}
+		gss_keytab=${DDNS_GSS_KEYTAB}
+		gss_principal=${DDNS_GSS_PRINCIPAL}
+		tsig_file=${DDNS_TSIG_FILE}
+		tsig_key_type=${DDNS_TSIG_KEY_TYPE}
+		tsig_key_name=${DDNS_TSIG_KEY_NAME}
+		tsig_key_secret=${DDNS_TSIG_KEY_SECRET}
+
+		echo replace $DDNS_REPLACE
+		if check_ip "$rr_name" "$rr_data" "$replace"; then
+			run_nsupdate "${rr_name}" "${ttl}" "${type}" "${rr_data}" "${replace}" "${server}" "${tcp}" "${zone}" "${gss_tsig}" "${gss_keytab}" "${gss_principal}" "${tsig_file}" "${tsig_key_type}" "${tsig_key_name}" "${tsig_key_secret}"
+		fi
+	fi
+
+	#
+	# Update DDNS*_HOSTNAME
+	#
+	while [ -n "$(eval echo \$$(echo DDNS${hostnum}_HOSTNAME))" ]; do
+		rr_name=$(eval echo "\${DDNS${hostnum}_HOSTNAME}")
+		ttl=$(eval echo "\${DDNS${hostnum}_TTL-\${DDNS_TTL:-300}}")
+		type=$(eval echo "\${DDNS${hostnum}_TYPE-\${DDNS_TYPE:-A}}")
+		rr_data=$ip_address
+		replace=$(eval echo "\${DDNS${hostnum}_REPLACE-\${DDNS_REPLACE:-yes}}")
+		server=$(eval echo "\${DDNS${hostnum}_SERVER-\${DDNS_SERVER}}")
+		tcp=$(eval echo "\${DDNS${hostnum}_TCP-\${DDNS_TCP:-no}}")
+		zone=$(eval echo "\${DDNS${hostnum}_ZONE-\${DDNS_ZONE}}")
+		gss_tsig=$(eval echo "\${DDNS${hostnum}_GSS_TSIG-\${DDNS_GSS_TSIG}}")
+		gss_keytab=$(eval echo "\${DDNS${hostnum}_GSS_KEYTAB-\${DDNS_GSS_KEYTAB}}")
+		gss_principal=$(eval echo "\${DDNS${hostnum}_GSS_PRINCIPAL-\${DDNS_GSS_PRINCIPAL}}")
+		tsig_file=$(eval echo "\${DDNS${hostnum}_TSIG_FILE-\${DDNS_TSIG_FILE}}")
+		tsig_key_type=$(eval echo "\${DDNS${hostnum}_TSIG_KEY_TYPE-\${DDNS_TSIG_KEY_TYPE}}")
+		tsig_key_name=$(eval echo "\${DDNS${hostnum}_TSIG_KEY_NAME-\${DDNS_TSIG_KEY_NAME}}")
+		tsig_key_secret=$(eval echo "\${DDNS${hostnum}_TSIG_KEY_SECRET-\${DDNS_TSIG_KEY_SECRET}}")
+
+		if check_ip "$rr_name" "$rr_data" "$replace"; then
+			run_nsupdate "${rr_name}" "${ttl}" "${type}" "${rr_data}" "${replace}" "${server}" "${tcp}" "${zone}" "${gss_tsig}" "${gss_keytab}" "${gss_principal}" "${tsig_file}" "${tsig_key_type}" "${tsig_key_name}" "${tsig_key_secret}"
+		fi
+		(( hostnum++ ))
+	done
+
+	#
+	# Update PTR record
+	#
+	if [ "x${DDNS_PTR}x" != "xnox" ]; then
+
+		# Do not update public IP if not forced with DDNS_PTR=yes
+		[ "x${public_ip}x" == "xyesx" ] && [ -z "${DDNS_PTR+x}" ] && return 0
+
+		# Get hostname for PTR update
+		rr_data=${DDNS_PTR_HOSTNAME-${DDNS_HOSTNAME-${DDNS0_HOSTNAME-${default_hostname}}}}
+		if [ -n "${rr_data}" ]; then
+			# Get reverse zone from IP address
+			local ADDR
+			IFS='.' read -ra ADDR <<< "$ip_address"
+			rr_name="${ADDR[3]}.${ADDR[2]}.${ADDR[1]}.${ADDR[0]}.in-addr.arpa"
+			type="PTR"
+			server=${DDNS_PTR_SERVER-${DDNS_SERVER}}
+			tcp=${DDNS_PTR_TCP-${DDNS_TCP:-yes}}
+			replace="yes"
+			ttl=${DDNS_PTR_TTL-${DDNS_TTL:=300}}
+			zone="${ADDR[2]}.${ADDR[1]}.${ADDR[0]}.in-addr.arpa"
+			gss_tsig=${DDNS_PTR_GSS_TSIG-${DDNS_GSS_TSIG}}
+			gss_keytab=${DDNS_PTR_GSS_KEYTAB-${DDNS_GSS_KEYTAB}}
+			gss_principal=${DDNS_PTR_GSS_PRINCIPAL-${DDNS_GSS_PRINCIPAL}}
+			tsig_file=${DDNS_PTR_TSIG_FILE-${DDNS_TSIG_FILE}}
+			tsig_key_type=${DDNS_PTR_TSIG_KEY_TYPE-${DDNS_TSIG_KEY_TYPE}}
+			tsig_key_name=${DDNS_PTR_TSIG_KEY_NAME-${DDNS_TSIG_KEY_NAME}}
+			tsig_key_secret=${DDNS_PTR_TSIG_KEY_SECRET-${DDNS_TSIG_KEY_SECRET}}
+
+			run_nsupdate "${rr_name}" "${ttl}" "${type}" "${rr_data}" "${replace}" "${server}" "${tcp}" "${zone}" "${gss_tsig}" "${gss_keytab}" "${gss_principal}" "${tsig_file}" "${tsig_key_type}" "${tsig_key_name}" "${tsig_key_secret}"
+		fi
+	fi
+}
+
+function get_all_ifaces() {
+	echo `ip addr show | sed -nr 's/([0-9]*: )(.*): .*/\2/p'`
+	return 0
+}
+
+function get_iface_ip() {
+	echo `ip addr show dev ${1} 2>/dev/null | sed -nr 's/.*inet ([^ \/]+).*/\1/p'`
+	return 0
+}
+
+function update_iface() {
+	local ip_address
+
+	[ "x${1}x" == "xlox" ] && return 0
+
+	# Unset all DDNS variables except DDNS_DEBUG
+	local DEBUG=${DDNS_DEBUG}
+	unset `compgen -v | grep "^DDNS.*"`
+	DDNS_DEBUG=$DEBUG
+
+	# Get address if not supplied
+	if [ $# -eq 1 ]; then
+		# Get interface address
+		ip_address=$(get_iface_ip "${1}")
+	else
+		ip_address=${2}
+	fi
+
+	# Skip if no address found
+	if [ "x${ip_address}x" == "xx" ]; then
+		return 1
+	fi
+
+	[ -f /etc/sysconfig/network ] && . /etc/sysconfig/network
+	[ -f /etc/sysconfig/networking/network ] && . /etc/sysconfig/networking/network
+
+	# Load interface config
+	cd /etc/sysconfig/network-scripts
+	CONFIG="${1}"
+	need_config ${CONFIG}
+	source_config >/dev/null 2>&1
+
+	if [ "x${DDNS}x" == "xnox" ] ; then
+		return 0
+	fi
+
+	parse_ddns_config "${ip_address}"
+	return 0
+}
+
+# Show usage if neeaded
+for var in "$@"
+do
+	if [ "$var" == "--help" ]; then
+		cat <<EOF
+Usage:
+	dnsupdate [[interface] [ip]]
+
+	--help -  Show usage
+EOF
+	fi
+done
+
+. /etc/sysconfig/network-scripts/network-functions
+. /etc/rc.d/init.d/functions
+
+
+if [[ $# -eq 1 ]] || [[ $# -eq 2 ]]; then
+	update_iface "${1}" "${2}"
+	exit 0
+fi
+
+# No parametars - try update all interfaces
+if [[ $# -eq 0 ]]; then
+	for iface in $(get_all_ifaces)
+	do
+		update_iface "${iface}"
+	done
+fi
\ No newline at end of file
diff --git a/dnsupdate.cron b/dnsupdate.cron
new file mode 100644
index 0000000..c57acab
--- /dev/null
+++ b/dnsupdate.cron
@@ -0,0 +1,2 @@
+# Run dnsupdate every 2 minutes
+*/2 * * * * root /usr/bin/dnsupdate > /dev/null 2>&1 || :
diff --git a/dnsupdate.spec b/dnsupdate.spec
new file mode 100644
index 0000000..62ca7e9
--- /dev/null
+++ b/dnsupdate.spec
@@ -0,0 +1,63 @@
+Summary:        Dynamic DNS for ppp and dhclient
+Name:           dnsupdate
+Version:        0.5.2
+Release:        1%{?dist}
+License:        GPLv2+
+Group:          System Environment/Daemons
+URL:            http://netst.org/pub/fedora/st/
+BuildArch:      noarch
+
+Requires:       initscripts
+Requires:       ppp
+Requires:       bind-utils
+
+Source0:        dnsupdate
+Source1:        dhclient-dnsupdate.sh
+Source2:        ppp-dnsupdate.sh
+Source3:        dnsupdate.cron
+
+BuildRoot: %{_tmppath}/%{name}-%{version}-%{release}-root-%(%{__id_u} -n)
+
+%description
+Dynamic DNS for ppp and dhclient.
+
+%install
+%{__rm} -rf %{buildroot}
+
+install -dm 755 $RPM_BUILD_ROOT%{_sysconfdir}
+install -dm 755 $RPM_BUILD_ROOT%{_sysconfdir}/cron.d
+install -dm 755 $RPM_BUILD_ROOT%{_bindir}
+install -dm 755 $RPM_BUILD_ROOT%{_sysconfdir}/dhcp/
+install -dm 755 $RPM_BUILD_ROOT%{_sysconfdir}/dhcp/dhclient.d
+install -dm 755 $RPM_BUILD_ROOT%{_sysconfdir}/ppp
+install -dm 755 $RPM_BUILD_ROOT%{_sysconfdir}/ppp/ip-up.d
+
+install -pm 755 %{SOURCE0} $RPM_BUILD_ROOT%{_bindir}/dnsupdate
+install -pm 755 %{SOURCE1} $RPM_BUILD_ROOT%{_sysconfdir}/dhcp/dhclient.d/dnsupdate.sh
+install -pm 755 %{SOURCE2} $RPM_BUILD_ROOT%{_sysconfdir}/ppp/ip-up.d/dnsupdate.sh
+install -pm 644 %{SOURCE3} $RPM_BUILD_ROOT%{_sysconfdir}/cron.d/dnsupdate
+
+%clean
+%{__rm} -rf %{buildroot}
+
+%files
+
+%defattr(-,root,root,-)
+
+%{_bindir}/dnsupdate
+%{_sysconfdir}/dhcp/dhclient.d/dnsupdate.sh
+%{_sysconfdir}/ppp/ip-up.d/dnsupdate.sh
+%{_sysconfdir}/cron.d/dnsupdate
+
+%changelog
+* Mon Jul 27 2015 Zoran Pericic <zpericic@netst.org> - 0.5.2-1
+- Fix dhcpd script
+
+* Sun Jul 26 2015 Zoran Pericic <zpericic@netst.org> - 0.5.1-1
+- Fix cron job and permissions
+
+* Wed Jul 22 2015 Zoran Pericic <zpericic@netst.org> - 0.5.0-1
+- Many improvements
+
+* Sun Apr 5 2015 Zoran Pericic <zpericic@netst.org>
+- Initial commmit
diff --git a/ppp-dnsupdate.sh b/ppp-dnsupdate.sh
new file mode 100755
index 0000000..457a677
--- /dev/null
+++ b/ppp-dnsupdate.sh
@@ -0,0 +1,10 @@
+#!/bin/bash
+
+[ -f "/etc/sysconfig/network-scripts/ifcfg-${6}" ] && . /etc/sysconfig/network-scripts/ifcfg-${6}
+
+if [[ $# -l 6 ]]; then
+	exit 0
+fi
+
+/usr/bin/dnsupdate "${6}" "${4}"
+