Fix errors setting '/proc/sys/net/ipv4/ip_dynaddr'.

conf/default_basic_behavior.conf

@@ -128,6 +128,38 @@ create_iperf_rules=false
 # --- Router IPv4
 # =============
 
+# - Activate forwarding
+# -
+# - Enable/disable forwarding to and between interfaces
+# -
+kernel_activate_forwarding=true
+
+# - Activate kernel support for dynamic IP adresses
+# - (not needed in case of static IP)
+# -
+# - see also https://www.frozentux.net/iptables-tutorial/other/ip_dynaddr.txt
+# -
+# - The values for the ip_dynaddr sysctl are [*]:
+# -
+# -   1:  To enable:
+# -   2:  To enable verbosity:
+# -
+# -  [*] At boot, by default no address rewriting is attempted.
+# -  [**] This code is currently totaly untested.
+# -
+# - Flags can be combined by adding them. Common settings
+# - would be:
+# -
+# - To enable rewriting in quiet mode:
+# -   # echo 1 > /proc/sys/net/ipv4/ip_dynaddr
+# - To enable rewriting in verbose mode:
+# -   # echo 2 > /proc/sys/net/ipv4/ip_dynaddr
+# - ...
+# -
+kernel_support_dynaddr=true
+default_dynaddr_flag=2
+
+
 # - Set to "true" to secure/tune the kernel
 # -
 adjust_kernel_parameters=true

conf/main_ipv4.conf.sample

@@ -1989,7 +1989,7 @@ kernel_activate_forwarding=true
 # - ...
 # -
 kernel_support_dynaddr=true
-dynaddr_flag="3"
+dynaddr_flag="$default_dynaddr_flag"
 
 # - Reduce DoS'ing ability by reducing timeouts
 # -

ipt-firewall-gateway

@@ -156,13 +156,20 @@ else
    echo_done
 fi
 
+if [[ -z "$dynaddr_flag" ]] ; then
+   dynaddr_flag=$default_dynaddr_flag
+fi
 if $kernel_support_dynaddr ; then
    echononl "\tActivate kernel support for dynamic addresses.."
-   if [[ -n $dynaddr_flag ]] && [[ $dynaddr_flag =~ ^-?[0-9]+$ ]]; then
+   if [[ -n $dynaddr_flag ]] && [[ $dynaddr_flag =~ ^-?[0-3]+$ ]]; then
       echo $dynaddr_flag > /proc/sys/net/ipv4/ip_dynaddr
       echo_done
    else
       echo_failed
+
+      echononl "\t\tSet '/proc/sys/net/ipv4/ip_dynaddr' to '2'"
+      echo 2 > /proc/sys/net/ipv4/ip_dynaddr
+      echo_done
    fi
 else
    echo 0 > /proc/sys/net/ipv4/ip_dynaddr