diff --git a/src/PVE/Network/SDN/Ipams/NetboxPlugin.pm b/src/PVE/Network/SDN/Ipams/NetboxPlugin.pm
index 18089b7..56a1787 100644
--- a/src/PVE/Network/SDN/Ipams/NetboxPlugin.pm
+++ b/src/PVE/Network/SDN/Ipams/NetboxPlugin.pm
@@ -25,6 +25,21 @@ sub options {
     };
 }
 
+sub netbox_api_request {
+    my ($config, $method, $path, $params) = @_;
+
+    return PVE::Network::SDN::api_request(
+	$method,
+	"$config->{url}${path}",
+	[
+	    'Content-Type' => 'application/json; charset=UTF-8',
+	    'Authorization' => "token $config->{token}"
+	],
+	$params,
+	$config->{fingerprint},
+    );
+}
+
 # Plugin implementation
 
 sub add_subnet {
@@ -32,62 +47,42 @@ sub add_subnet {
 
     my $cidr = $subnet->{cidr};
     my $gateway = $subnet->{gateway};
-    my $url = $plugin_config->{url};
-    my $token = $plugin_config->{token};
-    my $fingerprint = $plugin_config->{fingerprint};
-    my $headers = ['Content-Type' => 'application/json; charset=UTF-8', 'Authorization' => "token $token"];
 
-    my $internalid = get_prefix_id($url, $cidr, $headers, $fingerprint);
-
-    #create subnet
-    if (!$internalid) {
-
-	my $params = { prefix => $cidr };
-
-	eval {
-	    my $result = PVE::Network::SDN::api_request(
-		"POST", "$url/ipam/prefixes/", $headers, $params, $fingerprint );
-	};
-	if ($@) {
-	    die "error add subnet to ipam: $@" if !$noerr;
-	}
+    if (get_prefix_id($plugin_config, $cidr, $noerr)) {
+	return if $noerr;
+	die "prefix $cidr already exists in netbox";
+    }
+
+    eval {
+	netbox_api_request($plugin_config, "POST", "/ipam/prefixes/", {
+	    prefix => $cidr
+	});
+    };
+    if ($@) {
+	return if $noerr;
+	die "error adding subnet to ipam: $@";
     }
-   
 }
 
 sub del_subnet {
     my ($class, $plugin_config, $subnetid, $subnet, $noerr) = @_;
 
     my $cidr = $subnet->{cidr};
-    my $url = $plugin_config->{url};
-    my $token = $plugin_config->{token};
-    my $gateway = $subnet->{gateway};
-    my $fingerprint = $plugin_config->{fingerprint};
-    my $headers = ['Content-Type' => 'application/json; charset=UTF-8', 'Authorization' => "token $token"];
 
-    my $internalid = get_prefix_id($url, $cidr, $headers, $fingerprint);
-    return if !$internalid;
+    my $internalid = get_prefix_id($plugin_config, $cidr, $noerr);
 
     return; #fixme: check that prefix is empty exluding gateway, before delete
 
     eval {
-	PVE::Network::SDN::api_request(
-	    "DELETE", "$url/ipam/prefixes/$internalid/", $headers, undef, $fingerprint);
+	netbox_api_request($plugin_config, "DELETE", "/ipam/prefixes/$internalid/");
     };
-    if ($@) {
-	die "error deleting subnet from ipam: $@" if !$noerr;
-    }
-
+    die "error deleting subnet from ipam: $@" if $@ && !$noerr;
 }
 
 sub add_ip {
     my ($class, $plugin_config, $subnetid, $subnet, $ip, $hostname, $mac, $vmid, $is_gateway, $noerr) = @_;
 
     my $mask = $subnet->{mask};
-    my $url = $plugin_config->{url};
-    my $token = $plugin_config->{token};
-    my $fingerprint = $plugin_config->{fingerprint};
-    my $headers = ['Content-Type' => 'application/json; charset=UTF-8', 'Authorization' => "token $token"];
 
     my $description = undef;
     if ($is_gateway) {
@@ -96,18 +91,18 @@ sub add_ip {
 	$description = "mac:$mac";
     }
 
-    my $params = { address => "$ip/$mask", dns_name => $hostname, description => $description };
-
     eval {
-	PVE::Network::SDN::api_request(
-	    "POST", "$url/ipam/ip-addresses/", $headers, $params, $fingerprint);
+	netbox_api_request($plugin_config, "POST", "/ipam/ip-addresses/", {
+	    address => "$ip/$mask",
+	    dns_name => $hostname,
+	    description => $description,
+	});
     };
 
     if ($@) {
 	if ($is_gateway) {
-	    if (!is_ip_gateway($url, $ip, $headers, $fingerprint) && !$noerr) {
-		die "error add subnet ip to ipam: ip $ip already exist: $@";
-	    }
+	    die "error add subnet ip to ipam: ip $ip already exist: $@"
+		if !is_ip_gateway($plugin_config, $ip, $noerr);
 	} elsif (!$noerr) {
 	    die "error add subnet ip to ipam: ip already exist: $@";
 	}
@@ -118,11 +113,6 @@ sub update_ip {
     my ($class, $plugin_config, $subnetid, $subnet, $ip, $hostname, $mac, $vmid, $is_gateway, $noerr) = @_;
 
     my $mask = $subnet->{mask};
-    my $url = $plugin_config->{url};
-    my $token = $plugin_config->{token};
-    my $section = $plugin_config->{section};
-    my $fingerprint = $plugin_config->{fingerprint};
-    my $headers = ['Content-Type' => 'application/json; charset=UTF-8', 'Authorization' => "token $token"];
 
     my $description = undef;
     if ($is_gateway) {
@@ -131,14 +121,20 @@ sub update_ip {
 	$description = "mac:$mac";
     }
 
-    my $params = { address => "$ip/$mask", dns_name => $hostname, description => $description };
+    my $ip_id = get_ip_id($plugin_config, $ip, $noerr);
 
-    my $ip_id = get_ip_id($url, $ip, $headers, $fingerprint);
-    die "can't find ip $ip in ipam" if !$ip_id;
+    # definedness check, because ID could be 0
+    if (!defined($ip_id)) {
+	return if $noerr;
+	die "could not find id for ip address $ip";
+    }
 
     eval {
-	PVE::Network::SDN::api_request(
-	    "PATCH", "$url/ipam/ip-addresses/$ip_id/", $headers, $params, $fingerprint);
+	netbox_api_request($plugin_config, "PATCH", "/ipam/ip-addresses/$ip_id/", {
+	    address => "$ip/$mask",
+	    dns_name => $hostname,
+	    description => $description,
+	});
     };
     if ($@) {
 	die "error update ip $ip : $@" if !$noerr;
@@ -150,20 +146,22 @@ sub add_next_freeip {
 
     my $cidr = $subnet->{cidr};
 
-    my $url = $plugin_config->{url};
-    my $token = $plugin_config->{token};
-    my $fingerprint = $plugin_config->{fingerprint};
-    my $headers = ['Content-Type' => 'application/json; charset=UTF-8', 'Authorization' => "token $token"];
+    my $internalid = get_prefix_id($plugin_config, $cidr, $noerr);
 
-    my $internalid = get_prefix_id($url, $cidr, $headers, $fingerprint);
+    # definedness check, because ID could be 0
+    if (!defined($internalid)) {
+	return if $noerr;
+	die "could not find id for prefix $cidr";
+    }
 
     my $description = "mac:$mac" if $mac;
 
-    my $params = { dns_name => $hostname, description => $description };
-
     eval {
-	my $result = PVE::Network::SDN::api_request(
-	    "POST", "$url/ipam/prefixes/$internalid/available-ips/", $headers, $params, $fingerprint);
+	my $result = netbox_api_request($plugin_config, "POST", "/ipam/prefixes/$internalid/available-ips/", {
+	    dns_name => $hostname,
+	    description => $description,
+	});
+
 	my ($ip, undef) = split(/\//, $result->{address});
 	return $ip;
     };
@@ -176,19 +174,22 @@ sub add_next_freeip {
 sub add_range_next_freeip {
     my ($class, $plugin_config, $subnet, $range, $data, $noerr) = @_;
 
-    my $url = $plugin_config->{url};
-    my $token = $plugin_config->{token};
-    my $headers = ['Content-Type' => 'application/json; charset=UTF-8', 'Authorization' => "token $token"];
-    my $fingerprint = $plugin_config->{fingerprint};
+    my $internalid = get_iprange_id($plugin_config, $range, $noerr);
+
+    # definedness check, because ID could be 0
+    if (!defined($internalid)) {
+	return if $noerr;
+	die "could not find id for ip range $range->{'start-address'}:$range->{'end-address'}";
+    }
 
-    my $internalid = get_iprange_id($url, $range, $headers, $fingerprint);
     my $description = "mac:$data->{mac}" if $data->{mac};
 
-    my $params = { dns_name => $data->{hostname}, description => $description };
-
     eval {
-	my $result = PVE::Network::SDN::api_request(
-	    "POST", "$url/ipam/ip-ranges/$internalid/available-ips/", $headers, $params, $fingerprint);
+	my $result = netbox_api_request($plugin_config, "POST", "/ipam/ip-ranges/$internalid/available-ips/", {
+	    dns_name => $data->{hostname},
+	    description => $description,
+	});
+
 	my ($ip, undef) = split(/\//, $result->{address});
 	print "found ip free $ip in range $range->{'start-address'}-$range->{'end-address'}\n" if $ip;
 	return $ip;
@@ -204,16 +205,14 @@ sub del_ip {
 
     return if !$ip;
 
-    my $url = $plugin_config->{url};
-    my $token = $plugin_config->{token};
-    my $headers = ['Content-Type' => 'application/json; charset=UTF-8', 'Authorization' => "token $token"];
-    my $fingerprint = $plugin_config->{fingerprint};
-
-    my $ip_id = get_ip_id($url, $ip, $headers, $fingerprint);
-    die "can't find ip $ip in ipam" if !$ip_id;
+    my $ip_id = get_ip_id($plugin_config, $ip, $noerr);
+    if (!defined($ip_id)) {
+	warn "could not find id for ip $ip";
+	return;
+    }
 
     eval {
-	PVE::Network::SDN::api_request("DELETE", "$url/ipam/ip-addresses/$ip_id/", $headers, undef, $fingerprint);
+	netbox_api_request($plugin_config, "DELETE", "/ipam/ip-addresses/$ip_id/");
     };
     if ($@) {
 	die "error delete ip $ip : $@" if !$noerr;
@@ -221,18 +220,14 @@ sub del_ip {
 }
 
 sub get_ips_from_mac {
-    my ($class, $plugin_config, $mac, $zoneid) = @_;
-
-    my $url = $plugin_config->{url};
-    my $token = $plugin_config->{token};
-    my $headers = ['Content-Type' => 'application/json; charset=UTF-8', 'Authorization' => "token $token"];
-    my $fingerprint = $plugin_config->{fingerprint};
+    my ($class, $plugin_config, $mac, $zoneid, $noerr) = @_;
 
     my $ip4 = undef;
     my $ip6 = undef;
 
-    my $data = PVE::Network::SDN::api_request(
-	"GET", "$url/ipam/ip-addresses/?description__ic=$mac", $headers, undef, $fingerprint);
+    my $data = eval {
+	netbox_api_request($plugin_config, "GET", "/ipam/ip-addresses/?description__ic=$mac");
+    };
 
     for my $ip (@{$data->{results}}) {
 	if ($ip->{family}->{value} == 4 && !$ip4) {
@@ -247,18 +242,10 @@ sub get_ips_from_mac {
     return ($ip4, $ip6);
 }
 
-
 sub verify_api {
     my ($class, $plugin_config) = @_;
 
-    my $url = $plugin_config->{url};
-    my $token = $plugin_config->{token};
-    my $headers = ['Content-Type' => 'application/json; charset=UTF-8', 'Authorization' => "token $token"];
-    my $fingerprint = $plugin_config->{fingerprint};
-
-    eval {
-	PVE::Network::SDN::api_request("GET", "$url/ipam/aggregates/", $headers, undef, $fingerprint);
-    };
+    eval { netbox_api_request($plugin_config, "GET", "/ipam/aggregates/"); };
     if ($@) {
 	die "Can't connect to netbox api: $@";
     }
@@ -266,47 +253,71 @@ sub verify_api {
 
 sub on_update_hook {
     my ($class, $plugin_config) = @_;
-
-    PVE::Network::SDN::Ipams::NetboxPlugin::verify_api($class, $plugin_config);
+    verify_api($class, $plugin_config);
 }
 
-#helpers
-
+# helpers
 sub get_prefix_id {
-    my ($url, $cidr, $headers, $fingerprint) = @_;
-    my $result = PVE::Network::SDN::api_request(
-	"GET", "$url/ipam/prefixes/?q=$cidr", $headers, undef, $fingerprint);
+    my ($config, $cidr, $noerr) = @_;
+
+    # we need to supply any IP inside the prefix, without supplying the mask, so
+    # just take the one from the cidr
+    my ($ip, undef) = split(/\//, $cidr);
+
+    my $result = eval { netbox_api_request($config, "GET", "/ipam/prefixes/?q=$ip") };
+    if ($@) {
+	return if $noerr;
+	die "could not obtain ID for prefix $cidr: $@";
+    }
+
     my $data = @{$result->{results}}[0];
     my $internalid = $data->{id};
     return $internalid;
 }
 
 sub get_iprange_id {
-    my ($url, $range, $headers, $fingerprint) = @_;
-    my $result = PVE::Network::SDN::api_request(
-	"GET",
-	"$url/ipam/ip-ranges/?start_address=$range->{'start-address'}&end_address=$range->{'end-address'}",
-	$headers,
-	undef,
-	$fingerprint
-    );
+    my ($config, $range, $noerr) = @_;
+
+    my $result = eval {
+	netbox_api_request(
+	    $config,
+	    "GET",
+	    "/ipam/ip-ranges/?start_address=$range->{'start-address'}&end_address=$range->{'end-address'}",
+	);
+    };
+    if ($@) {
+	return if $noerr;
+	die "could not obtain ID for IP range $range->{'start-address'}:$range->{'end-address'}: $@";
+    }
+
     my $data = @{$result->{results}}[0];
     my $internalid = $data->{id};
     return $internalid;
 }
 
 sub get_ip_id {
-    my ($url, $ip, $headers, $fingerprint) = @_;
-    my $result = PVE::Network::SDN::api_request(
-	"GET", "$url/ipam/ip-addresses/?q=$ip", $headers, undef, $fingerprint);
+    my ($config, $ip, $noerr) = @_;
+
+    my $result = eval { netbox_api_request($config, "GET", "/ipam/ip-addresses/?q=$ip") };
+    if ($@) {
+	return if $noerr;
+	die "could not obtain ID for IP $ip: $@";
+    }
+
     my $data = @{$result->{results}}[0];
     my $ip_id = $data->{id};
     return $ip_id;
 }
 
 sub is_ip_gateway {
-    my ($url, $ip, $headers, $fingerprint) = @_;
-    my $result = PVE::Network::SDN::api_request("GET", "$url/ipam/ip-addresses/?q=$ip", $headers, undef, $fingerprint);
+    my ($config, $ip, $noerr) = @_;
+
+    my $result = eval { netbox_api_request($config, "GET", "/ipam/ip-addresses/?q=$ip") };
+    if ($@) {
+	return if $noerr;
+	die "could not obtain ipam entry for address $ip: $@";
+    }
+
     my $data = @{$result->{data}}[0];
     my $description = $data->{description};
     my $is_gateway = 1 if $description eq 'gateway';