Thx for this patch.
It resolves a problem, which shows up from time to time.
It allows some freedom in defining fixed leases ( without interpretation 
of sense ), but marks this exception of the 'IPFire philosophy'.

Bernhard

Reviewed-by: Bernhard Bitsch <bbitsch(a)ipfire.org>

Am 13.02.2023 um 18:55 schrieb Adolf Belka:
> - This patch marks all IP's that are in the Fixed list but are also in the dynamic range
>     that has been defined, in red.
> - Additional function created to check if an ip address is in a defined range.
> - Added an additional key item under the Fixed Leases table for Fixed IP in dynamic range
> - Added line to English Language file for this key item.
> - ./make lang run before commit.
> - Tested in vm testbed and confirmed that any ip address in the Fixed Leases table that
>     is in the defined dynamic range is highlighted in red
> - This uses the css background-color appoach from the first patch in this set.
> - This patch only highlights those IP's that overlap in red but does nothing more. So a
>     user can still create new ones if they want but they will all show up in red.
> - I may come back at a later time with a further patch that allows IP's that overlap but
>     are in the existing leases file to continue being used and edited but prevents new IP's
>     that overlap from being created.
> - This patch flags up if people are doing things that they shouldn't be doing but allows
>     them to continue doing so without changing anything if they don't want to.
> 
> Tested-by: Adolf Belka <adolf.belka(a)ipfire.org>
> Signed-off-by: Adolf Belka <adolf.belka(a)ipfire.org>
> ---
>   config/cfgroot/network-functions.pl | 24 +++++++++++++++++++++++
>   doc/language_issues.de              |  2 +-
>   doc/language_issues.en              |  2 +-
>   doc/language_issues.es              |  2 ++
>   doc/language_issues.fr              | 15 ++++++---------
>   doc/language_issues.it              |  2 +-
>   doc/language_issues.nl              |  2 +-
>   doc/language_issues.pl              |  2 +-
>   doc/language_issues.ru              |  2 +-
>   doc/language_issues.tr              |  2 +-
>   doc/language_missings               | 15 ++++++++-------
>   html/cgi-bin/dhcp.cgi               | 30 ++++++++++++++++++++++-------
>   langs/en/cgi-bin/en.pl              |  1 +
>   13 files changed, 71 insertions(+), 30 deletions(-)
> 
> diff --git a/config/cfgroot/network-functions.pl b/config/cfgroot/network-functions.pl
> index 4ac6d8670..7b38cfac7 100644
> --- a/config/cfgroot/network-functions.pl
> +++ b/config/cfgroot/network-functions.pl
> @@ -307,6 +307,24 @@ sub ip_address_in_network($$) {
>   	return (($address_bin >= $network_bin) && ($address_bin <= $broadcast_bin));
>   }
>   
> +# Returns True if $ipaddress is within $ipstart and $ipend range.
> +sub ip_address_in_range($$) {
> +	my $ipaddress = shift;
> +	my $ipstart = shift;
> +	my $ipend = shift;
> +
> +	my $ipaddress_bin = &ip2bin($ipaddress);
> +	return undef unless (defined $ipaddress_bin);
> +
> +	my $ipstart_bin = &ip2bin($ipstart);
> +	return undef unless (defined $ipstart_bin);
> +
> +	my $ipend_bin = &ip2bin($ipend);
> +	return undef unless (defined $ipend_bin);
> +
> +	return (($ipaddress_bin >= $ipstart_bin) && ($ipaddress_bin <= $ipend_bin));
> +}
> +
>   sub setup_upstream_proxy() {
>   	my %proxysettings = ();
>   	&General::readhash("${General::swroot}/proxy/settings", \%proxysettings);
> @@ -666,6 +684,12 @@ sub testsuite() {
>   	$result = &ip_address_in_network("192.168.30.11", "0.0.0.0/8");
>   	assert('ip_address_in_network("192.168.30.11", "0.0.0.0/8")', !$result);
>   
> +	$result = &ip_address_in_range("192.168.30.11", "192.168.30.10", "192.168.30.20");
> +	assert('ip_address_in_range("192.168.30.11", "192.168.30.10", "192.168.30.20")', $result);
> +
> +	$result = &ip_address_in_range("192.168.30.21", "192.168.30.10", "192.168.30.20");
> +	assert('ip_address_in_range("192.168.30.21", "192.168.30.10", "192.168.30.20")', !$result);
> +
>   	print "Testsuite completed successfully!\n";
>   
>   	return 0;
> diff --git a/doc/language_issues.de b/doc/language_issues.de
> index 88c7879be..392416192 100644
> --- a/doc/language_issues.de
> +++ b/doc/language_issues.de
> @@ -883,7 +883,7 @@ WARNING: untranslated string: cake profile pppoe-ptm 27 = PPPoE PTM (27 bytes)
>   WARNING: untranslated string: cake profile pppoe-vcmux 32 = PPPoE VC-MUX (32 bytes)
>   WARNING: untranslated string: cake profile raw 0 = Raw (no overhead compensation)
>   WARNING: untranslated string: desired = Desired
> -WARNING: untranslated string: dh parameter = unknown string
> +WARNING: untranslated string: dhcp fixed ip address in dynamic range = Fixed IP Address in dynamic range
>   WARNING: untranslated string: disable = Disable
>   WARNING: untranslated string: download apple profile = Download Apple Configuration Profile
>   WARNING: untranslated string: enable = Enable
> diff --git a/doc/language_issues.en b/doc/language_issues.en
> index c29e3bed6..08fda35b7 100644
> --- a/doc/language_issues.en
> +++ b/doc/language_issues.en
> @@ -574,7 +574,6 @@ WARNING: untranslated string: details = Details
>   WARNING: untranslated string: device = Device
>   WARNING: untranslated string: devices on blue = Devices on BLUE
>   WARNING: untranslated string: dh = Diffie-Hellman-Parameter
> -WARNING: untranslated string: dh parameter = unknown string
>   WARNING: untranslated string: dhcp advopt add = Add a DHCP option
>   WARNING: untranslated string: dhcp advopt added = DHCP option added
>   WARNING: untranslated string: dhcp advopt blank value = DHCP Option value cannot be empty.
> @@ -601,6 +600,7 @@ WARNING: untranslated string: dhcp dns key name = Key Name
>   WARNING: untranslated string: dhcp dns update = DNS Update
>   WARNING: untranslated string: dhcp dns update algo = Algorithm
>   WARNING: untranslated string: dhcp dns update secret = Secret
> +WARNING: untranslated string: dhcp fixed ip address in dynamic range = Fixed IP Address in dynamic range
>   WARNING: untranslated string: dhcp make fixed lease = Add to fix leases
>   WARNING: untranslated string: dhcp server = DHCP Server
>   WARNING: untranslated string: dhcp server disabled = DHCP server disabled.  Stopped.
> diff --git a/doc/language_issues.es b/doc/language_issues.es
> index 0bd390d5d..ffe423bd1 100644
> --- a/doc/language_issues.es
> +++ b/doc/language_issues.es
> @@ -228,6 +228,7 @@ WARNING: translation string unused: dh key move failed
>   WARNING: translation string unused: dh key warn
>   WARNING: translation string unused: dh key warn1
>   WARNING: translation string unused: dh name is invalid
> +WARNING: translation string unused: dh parameter
>   WARNING: translation string unused: dhcp base ip fixed lease
>   WARNING: translation string unused: dhcp create fixed leases
>   WARNING: translation string unused: dhcp fixed lease err1
> @@ -943,6 +944,7 @@ WARNING: untranslated string: access point name is invalid = Access Point Name i
>   WARNING: untranslated string: access point name is required = Access Point Name is required
>   WARNING: untranslated string: bytes = unknown string
>   WARNING: untranslated string: cpu frequency = CPU frequency
> +WARNING: untranslated string: dhcp fixed ip address in dynamic range = Fixed IP Address in dynamic range
>   WARNING: untranslated string: dns servers = DNS Servers
>   WARNING: untranslated string: error message = unknown string
>   WARNING: untranslated string: fwhost cust locationgrp = unknown string
> diff --git a/doc/language_issues.fr b/doc/language_issues.fr
> index 56d69d86e..cb06f0ab3 100644
> --- a/doc/language_issues.fr
> +++ b/doc/language_issues.fr
> @@ -392,7 +392,6 @@ WARNING: translation string unused: generatepolicy
>   WARNING: translation string unused: generatereport
>   WARNING: translation string unused: genkey
>   WARNING: translation string unused: green interface
> -WARNING: translation string unused: guaranteed bandwith
>   WARNING: translation string unused: guest ok
>   WARNING: translation string unused: gz with key
>   WARNING: translation string unused: harddisk temperature graphs
> @@ -404,6 +403,7 @@ WARNING: translation string unused: host deny
>   WARNING: translation string unused: hostname and domain already in use
>   WARNING: translation string unused: hour-graph
>   WARNING: translation string unused: hours2
> +WARNING: translation string unused: ibod for dual isdn only
>   WARNING: translation string unused: icmp selected but no type
>   WARNING: translation string unused: icmp type
>   WARNING: translation string unused: id
> @@ -453,6 +453,10 @@ WARNING: translation string unused: ipblocklist category scanner
>   WARNING: translation string unused: ipfire side
>   WARNING: translation string unused: ipsec no connections
>   WARNING: translation string unused: iptable rules
> +WARNING: translation string unused: isdn
> +WARNING: translation string unused: isdn settings
> +WARNING: translation string unused: isdn1
> +WARNING: translation string unused: isdn2
>   WARNING: translation string unused: javascript menu error1
>   WARNING: translation string unused: javascript menu error2
>   WARNING: translation string unused: kernel version
> @@ -908,15 +912,11 @@ WARNING: translation string unused: zoneconf val zoneslave amount error
>   WARNING: untranslated string: access point name = Access Point Name
>   WARNING: untranslated string: access point name is invalid = Access Point Name is invalid
>   WARNING: untranslated string: access point name is required = Access Point Name is required
> -WARNING: untranslated string: advproxy errmsg invalid url = Invalid URL
>   WARNING: untranslated string: core notice 3 = available.
> -WARNING: untranslated string: dh = Diffie-Hellman-Parameter
> -WARNING: untranslated string: dh parameter = unknown string
> -WARNING: untranslated string: email recipient invalid = Invalid email recipient
> +WARNING: untranslated string: dhcp fixed ip address in dynamic range = Fixed IP Address in dynamic range
>   WARNING: untranslated string: error message = unknown string
>   WARNING: untranslated string: fwhost cust locationgrp = unknown string
>   WARNING: untranslated string: fwhost err hostip = unknown string
> -WARNING: untranslated string: guaranteed bandwidth = Guaranteed bandwidth
>   WARNING: untranslated string: guardian block a host = unknown string
>   WARNING: untranslated string: guardian block httpd brute-force = unknown string
>   WARNING: untranslated string: guardian block ssh brute-force = unknown string
> @@ -947,9 +947,6 @@ WARNING: untranslated string: guardian logtarget_syslog = unknown string
>   WARNING: untranslated string: guardian no entries = unknown string
>   WARNING: untranslated string: guardian service = unknown string
>   WARNING: untranslated string: pakfire ago = ago.
> -WARNING: untranslated string: retbleed = Retbleed
>   WARNING: untranslated string: route config changed = unknown string
>   WARNING: untranslated string: routing config added = unknown string
>   WARNING: untranslated string: routing config changed = unknown string
> -WARNING: untranslated string: service boot setting unavailable = No valid runlevel symlink was found for the initscript of this service.
> -WARNING: untranslated string: show dh = Show Diffie-Hellman parameters
> diff --git a/doc/language_issues.it b/doc/language_issues.it
> index 9999f947c..dd794f57a 100644
> --- a/doc/language_issues.it
> +++ b/doc/language_issues.it
> @@ -940,13 +940,13 @@ WARNING: untranslated string: dangerous = Dangerous
>   WARNING: untranslated string: default IP address = Default IP Address
>   WARNING: untranslated string: desired = Desired
>   WARNING: untranslated string: dh = Diffie-Hellman-Parameter
> -WARNING: untranslated string: dh parameter = unknown string
>   WARNING: untranslated string: dhcp deny known clients: = Deny known clients:
>   WARNING: untranslated string: dhcp dns enable update = Enable DNS Update (RFC2136):
>   WARNING: untranslated string: dhcp dns key name = Key Name
>   WARNING: untranslated string: dhcp dns update = DNS Update
>   WARNING: untranslated string: dhcp dns update algo = Algorithm
>   WARNING: untranslated string: dhcp dns update secret = Secret
> +WARNING: untranslated string: dhcp fixed ip address in dynamic range = Fixed IP Address in dynamic range
>   WARNING: untranslated string: dhcp make fixed lease = Add to fix leases
>   WARNING: untranslated string: dhcp valid range required when deny known clients checked = Valid range required when "Deny known clients:" is checked
>   WARNING: untranslated string: disable = Disable
> diff --git a/doc/language_issues.nl b/doc/language_issues.nl
> index 14a7b420e..4f100abd2 100644
> --- a/doc/language_issues.nl
> +++ b/doc/language_issues.nl
> @@ -943,12 +943,12 @@ WARNING: untranslated string: default = Default
>   WARNING: untranslated string: default IP address = Default IP Address
>   WARNING: untranslated string: desired = Desired
>   WARNING: untranslated string: dh = Diffie-Hellman-Parameter
> -WARNING: untranslated string: dh parameter = unknown string
>   WARNING: untranslated string: dhcp dns enable update = Enable DNS Update (RFC2136):
>   WARNING: untranslated string: dhcp dns key name = Key Name
>   WARNING: untranslated string: dhcp dns update = DNS Update
>   WARNING: untranslated string: dhcp dns update algo = Algorithm
>   WARNING: untranslated string: dhcp dns update secret = Secret
> +WARNING: untranslated string: dhcp fixed ip address in dynamic range = Fixed IP Address in dynamic range
>   WARNING: untranslated string: dhcp make fixed lease = Add to fix leases
>   WARNING: untranslated string: disable = Disable
>   WARNING: untranslated string: disconnected = Disconnected
> diff --git a/doc/language_issues.pl b/doc/language_issues.pl
> index a53a208d9..e91e62c5b 100644
> --- a/doc/language_issues.pl
> +++ b/doc/language_issues.pl
> @@ -915,13 +915,13 @@ WARNING: untranslated string: default IP address = Default IP Address
>   WARNING: untranslated string: desired = Desired
>   WARNING: untranslated string: details = Details
>   WARNING: untranslated string: dh = Diffie-Hellman-Parameter
> -WARNING: untranslated string: dh parameter = unknown string
>   WARNING: untranslated string: dhcp deny known clients: = Deny known clients:
>   WARNING: untranslated string: dhcp dns enable update = Enable DNS Update (RFC2136):
>   WARNING: untranslated string: dhcp dns key name = Key Name
>   WARNING: untranslated string: dhcp dns update = DNS Update
>   WARNING: untranslated string: dhcp dns update algo = Algorithm
>   WARNING: untranslated string: dhcp dns update secret = Secret
> +WARNING: untranslated string: dhcp fixed ip address in dynamic range = Fixed IP Address in dynamic range
>   WARNING: untranslated string: dhcp make fixed lease = Add to fix leases
>   WARNING: untranslated string: dhcp valid range required when deny known clients checked = Valid range required when "Deny known clients:" is checked
>   WARNING: untranslated string: disable = Disable
> diff --git a/doc/language_issues.ru b/doc/language_issues.ru
> index c5dc1aa61..7dd1a63d7 100644
> --- a/doc/language_issues.ru
> +++ b/doc/language_issues.ru
> @@ -911,13 +911,13 @@ WARNING: untranslated string: default IP address = Default IP Address
>   WARNING: untranslated string: desired = Desired
>   WARNING: untranslated string: details = Details
>   WARNING: untranslated string: dh = Diffie-Hellman-Parameter
> -WARNING: untranslated string: dh parameter = unknown string
>   WARNING: untranslated string: dhcp deny known clients: = Deny known clients:
>   WARNING: untranslated string: dhcp dns enable update = Enable DNS Update (RFC2136):
>   WARNING: untranslated string: dhcp dns key name = Key Name
>   WARNING: untranslated string: dhcp dns update = DNS Update
>   WARNING: untranslated string: dhcp dns update algo = Algorithm
>   WARNING: untranslated string: dhcp dns update secret = Secret
> +WARNING: untranslated string: dhcp fixed ip address in dynamic range = Fixed IP Address in dynamic range
>   WARNING: untranslated string: dhcp make fixed lease = Add to fix leases
>   WARNING: untranslated string: dhcp valid range required when deny known clients checked = Valid range required when "Deny known clients:" is checked
>   WARNING: untranslated string: disable = Disable
> diff --git a/doc/language_issues.tr b/doc/language_issues.tr
> index 552082a96..3443b1f1a 100644
> --- a/doc/language_issues.tr
> +++ b/doc/language_issues.tr
> @@ -926,8 +926,8 @@ WARNING: untranslated string: dangerous = Dangerous
>   WARNING: untranslated string: default IP address = Default IP Address
>   WARNING: untranslated string: desired = Desired
>   WARNING: untranslated string: dh = Diffie-Hellman-Parameter
> -WARNING: untranslated string: dh parameter = unknown string
>   WARNING: untranslated string: dhcp deny known clients: = Deny known clients:
> +WARNING: untranslated string: dhcp fixed ip address in dynamic range = Fixed IP Address in dynamic range
>   WARNING: untranslated string: dhcp make fixed lease = Add to fix leases
>   WARNING: untranslated string: dhcp valid range required when deny known clients checked = Valid range required when "Deny known clients:" is checked
>   WARNING: untranslated string: disable = Disable
> diff --git a/doc/language_missings b/doc/language_missings
> index 65d38b422..78b9e8a2d 100644
> --- a/doc/language_missings
> +++ b/doc/language_missings
> @@ -47,6 +47,7 @@
>   < could not connect to www ipfire org
>   < cryptographic settings
>   < desired
> +< dhcp fixed ip address in dynamic range
>   < dhcp server disabled on blue interface
>   < dhcp server enabled on blue interface
>   < disable
> @@ -102,6 +103,7 @@
>   < access point name is required
>   < addon
>   < cpu frequency
> +< dhcp fixed ip address in dynamic range
>   < dns servers
>   < hardware vulnerabilities
>   < invalid ip or hostname
> @@ -115,18 +117,12 @@
>   < access point name
>   < access point name is invalid
>   < access point name is required
> -< advproxy errmsg invalid url
>   < ansi t1.483
>   < bewan adsl pci st
>   < bewan adsl usb
> -< dh
> -< email recipient invalid
> +< dhcp fixed ip address in dynamic range
>   < g.dtm
>   < g.lite
> -< guaranteed bandwidth
> -< retbleed
> -< service boot setting unavailable
> -< show dh
>   < upload fcdsl.o
>   ############################################################################
>   # Checking cgi-bin translations for language: it                           #
> @@ -252,6 +248,7 @@
>   < dhcp dns update
>   < dhcp dns update algo
>   < dhcp dns update secret
> +< dhcp fixed ip address in dynamic range
>   < dhcp make fixed lease
>   < dhcp valid range required when deny known clients checked
>   < disable
> @@ -756,6 +753,7 @@
>   < dhcp dns update
>   < dhcp dns update algo
>   < dhcp dns update secret
> +< dhcp fixed ip address in dynamic range
>   < dhcp make fixed lease
>   < disable
>   < Disabled
> @@ -1353,6 +1351,7 @@
>   < dhcp dns update
>   < dhcp dns update algo
>   < dhcp dns update secret
> +< dhcp fixed ip address in dynamic range
>   < dhcp make fixed lease
>   < dhcp valid range required when deny known clients checked
>   < disable
> @@ -2330,6 +2329,7 @@
>   < dhcp dns update
>   < dhcp dns update algo
>   < dhcp dns update secret
> +< dhcp fixed ip address in dynamic range
>   < dhcp make fixed lease
>   < dhcp valid range required when deny known clients checked
>   < disable
> @@ -3173,6 +3173,7 @@
>   < desired
>   < dh
>   < dhcp deny known clients:
> +< dhcp fixed ip address in dynamic range
>   < dhcp make fixed lease
>   < dhcp valid range required when deny known clients checked
>   < disable
> diff --git a/html/cgi-bin/dhcp.cgi b/html/cgi-bin/dhcp.cgi
> index 2d162b204..1b1102932 100644
> --- a/html/cgi-bin/dhcp.cgi
> +++ b/html/cgi-bin/dhcp.cgi
> @@ -127,6 +127,9 @@ my $extraHead = <<END
>   	}
>   	.cell-orange {
>   		background-color: orange;
> +	}
> +	.cell-red {
> +		background-color: red;
>   	}		
>   </style>
>   END
> @@ -1042,8 +1045,9 @@ my $ipdup = 0;
>   my %ipinuse = ();
>   my %macdupl = (); # Duplicate MACs have to be on different subnets
>   my %ipoutside = ();
> +my %ipinrange = ();
>   
> -# mark duplicate ip or duplicate MAC
> +# mark duplicate IP, duplicate MAC or IP in dynamic range
>   foreach my $line (@current2) {
>       my @temp = split(/\,/,$line);
>       $macdupl{$temp[0]} += 1;
> @@ -1054,14 +1058,21 @@ foreach my $line (@current2) {
>       if ($ipinuse{$temp[1]} > 1) {
>   	$ipdup = 1; 	# Flag up duplicates for use later
>       }
> -    # Mark IP addresses outwith known subnets
>       $ipoutside{$temp[1]} = 1;
> +    $ipinrange{$temp[1]} = 0;
>       foreach my $itf (@ITFs) {
> -        if ( &General::IpInSubnet($temp[1],
> -                $netsettings{"${itf}_NETADDRESS"},
> -                $netsettings{"${itf}_NETMASK"})) {
> -            $ipoutside{$temp[1]} = 0;
> -        }
> +    # Mark IP addresses outwith known subnets
> +            	if ( &General::IpInSubnet($temp[1],
> +                	$netsettings{"${itf}_NETADDRESS"},
> +                	$netsettings{"${itf}_NETMASK"})) {
> +            	   $ipoutside{$temp[1]} = 0;
> +        	}
> +    # Mark IP addresses that overlap with dynamic range
> +	    	if (&Network::ip_address_in_range($temp[1],
> +		        $dhcpsettings{"START_ADDR_${itf}"},
> +		        $dhcpsettings{"END_ADDR_${itf}"})) {
> +            	   $ipinrange{$temp[1]} = 1;
> +        	}
>       }
>   }
>   
> @@ -1115,6 +1126,9 @@ foreach my $line (@current2) {
>       if ($ipoutside{$temp[1]} > 0) {
>   	$TAG4 = "class='cell-orange'" if ($dhcpsettings{'KEY2'} ne $key);
>       }
> +    if ($ipinrange{$temp[1]} > 0) {
> +	$TAG4 = "class='cell-red'" if ($dhcpsettings{'KEY2'} ne $key);
> +    }
>   
>       print <<END
>   <td align='center' $col>$TAG2$temp[0]$TAG3</td>
> @@ -1177,6 +1191,8 @@ print <<END
>   	<td>&nbsp;</td>
>   	<td>&nbsp;</td>
>   	<td class='base cell-orange'>$Lang::tr{'ip address outside subnets'}</td>
> +        <td>&nbsp;&nbsp</td>
> +        <td class='base cell-red'>$Lang::tr{'dhcp fixed ip address in dynamic range'}</td>
>   	<td>&nbsp;</td>
>   	<td>&nbsp;</td>
>   	$dup
> diff --git a/langs/en/cgi-bin/en.pl b/langs/en/cgi-bin/en.pl
> index 80753b841..5a72f53b8 100644
> --- a/langs/en/cgi-bin/en.pl
> +++ b/langs/en/cgi-bin/en.pl
> @@ -827,6 +827,7 @@
>   'dhcp dns update' => 'DNS Update',
>   'dhcp dns update algo' => 'Algorithm',
>   'dhcp dns update secret' => 'Secret',
> +'dhcp fixed ip address in dynamic range' => 'Fixed IP Address in dynamic range',
>   'dhcp fixed lease err1' => 'For a fix lease you have to enter the MAC address or the hostname, or you enter both.',
>   'dhcp fixed lease help1' => 'IP Addresses might be entered as FQDN',
>   'dhcp make fixed lease' => 'Add to fix leases',