diff --git a/src/ethernet.c b/src/ethernet.c
index 3c11d10..e249a77 100644
--- a/src/ethernet.c
+++ b/src/ethernet.c
@@ -154,17 +154,15 @@ bool ethII_frame_unpack(const novell_ipx_packet **packet, size_t *packet_len, co
 
 size_t novell_frame_size(size_t ipx_payload_len)
 {
-	static const size_t OVERHEAD
-		= sizeof(ethernet_header)
-		+ sizeof(novell_ipx_packet);
-	
 	if(ipx_payload_len > NOVELL_IPX_PACKET_MAX_PAYLOAD
-		|| ipx_payload_len > (1500 - OVERHEAD))
+		|| ipx_payload_len > (1500 - sizeof(novell_ipx_packet)))
 	{
 		return 0;
 	}
 	
-	return OVERHEAD + ipx_payload_len;
+	return sizeof(ethernet_header)
+		+ sizeof(novell_ipx_packet)
+		+ ipx_payload_len;
 }
 
 void novell_frame_pack(void *frame_buffer,
@@ -224,18 +222,16 @@ bool novell_frame_unpack(const novell_ipx_packet **packet, size_t *packet_len, c
 
 size_t llc_frame_size(size_t ipx_payload_len)
 {
-	static const size_t OVERHEAD
-		= sizeof(ethernet_header)
-		+ sizeof(llc_header)
-		+ sizeof(novell_ipx_packet);
-	
 	if(ipx_payload_len > NOVELL_IPX_PACKET_MAX_PAYLOAD
-		|| ipx_payload_len > (1500 - OVERHEAD))
+		|| ipx_payload_len > (1500 - (sizeof(llc_header) + sizeof(novell_ipx_packet))))
 	{
 		return 0;
 	}
 	
-	return OVERHEAD + ipx_payload_len;
+	return sizeof(ethernet_header)
+		+ sizeof(llc_header)
+		+ sizeof(novell_ipx_packet)
+		+ ipx_payload_len;
 }
 
 void llc_frame_pack(void *frame_buffer,
diff --git a/tests/30-eth-ipx.t b/tests/30-eth-ipx.t
index 24a0da0..2e21130 100644
--- a/tests/30-eth-ipx.t
+++ b/tests/30-eth-ipx.t
@@ -44,6 +44,7 @@ my $node_c_net = "00:00:00:00";
 
 my $ipx_eth_capture_class;
 my $ipx_eth_send_func;
+my $max_payload_size;
 
 shared_examples_for "ipx over ethernet" => sub
 {
@@ -502,6 +503,96 @@ shared_examples_for "ipx over ethernet" => sub
 		};
 	};
 	
+	it "can transmit the largest possible packet" => sub
+	{
+		my $capture = $ipx_eth_capture_class->new($local_dev_a);
+		
+		run_remote_cmd(
+			$remote_ip_a, "Z:\\tools\\ipx-send.exe",
+			"-l" => $max_payload_size,
+			"-s" => "4324", "-h" => $remote_mac_a,
+			"00:00:00:01", $local_mac_a, "6789",
+		);
+		
+		sleep(1);
+		
+		my @packets = $capture->read_available();
+		
+		cmp_hashes_partial(\@packets, [
+			{
+				src_network => "00:00:00:01",
+				src_node    => $remote_mac_a,
+				src_socket  => 4324,
+				
+				dst_network => "00:00:00:01",
+				dst_node    => $local_mac_a,
+				dst_socket  => 6789,
+				
+				data => (chr(0xAA) x $max_payload_size),
+			},
+		]);
+	};
+	
+	it "refuses to transmit larger than the largest possible packet" => sub
+	{
+		my $capture = $ipx_eth_capture_class->new($local_dev_a);
+		
+		trap {
+			run_remote_cmd(
+				$remote_ip_a, "Z:\\tools\\ipx-send.exe",
+				"-l" => $max_payload_size + 1,
+				"-s" => "1111", "-h" => $remote_mac_a,
+				"00:00:00:01", $local_mac_a, "2222",
+			);
+		};
+		
+		sleep(1);
+		
+		# Ensure sendto() failed with WSAEMSGSIZE
+		like($trap->die(), qr/^sendto: 10040$/m);
+		
+		# Ensure no packets were transmitted.
+		my @packets = $capture->read_available();
+		cmp_hashes_partial(\@packets, []);
+	};
+	
+	it "can receive the largest possible packet" => sub
+	{
+		my $capture = IPXWrapper::Tool::IPXRecv->new(
+			$remote_ip_a,
+			"00:00:00:00", $remote_mac_a, "3456",
+		);
+		
+		$ipx_eth_send_func->($local_dev_a,
+			tc   => 0,
+			type => 0,
+			
+			dest_network => "00:00:00:01",
+			dest_node    => $remote_mac_a,
+			dest_socket  => 3456,
+			
+			src_network  => "00:00:00:01",
+			src_node     => $local_mac_a,
+			src_socket   => 4567,
+			
+			data => ("x" x $max_payload_size),
+		);
+		
+		sleep(1);
+		
+		my @packets = $capture->kill_and_read();
+		
+		cmp_hashes_partial(\@packets, [
+			{
+				src_network => "00:00:00:01",
+				src_node    => $local_mac_a,
+				src_socket  => 4567,
+				
+				data => ("x" x $max_payload_size),
+			},
+		]);
+	};
+	
 	before all => sub
 	{
 		$ptype_capture_class = $ipx_eth_capture_class;
@@ -542,6 +633,7 @@ describe "IPXWrapper using Ethernet encapsulation" => sub
 		
 		$ipx_eth_capture_class = "IPXWrapper::Capture::IPX";
 		$ipx_eth_send_func     = \&send_ipx_packet_ethernet;
+		$max_payload_size      = 1470;
 	};
 	
 	it_should_behave_like "ipx over ethernet";
@@ -559,6 +651,7 @@ describe "IPXWrapper using Novell Ethernet encapsulation" => sub
 		
 		$ipx_eth_capture_class = "IPXWrapper::Capture::IPXNovell";
 		$ipx_eth_send_func     = \&send_ipx_packet_novell;
+		$max_payload_size      = 1470;
 	};
 	
 	it_should_behave_like "ipx over ethernet";
@@ -576,6 +669,7 @@ describe "IPXWrapper using LLC (802.2) Ethernet encapsulation" => sub
 		
 		$ipx_eth_capture_class = "IPXWrapper::Capture::IPXLLC";
 		$ipx_eth_send_func     = \&send_ipx_packet_llc;
+		$max_payload_size      = 1467;
 	};
 	
 	it_should_behave_like "ipx over ethernet";
diff --git a/tests/ethernet.c b/tests/ethernet.c
index dd527c8..6190abd 100644
--- a/tests/ethernet.c
+++ b/tests/ethernet.c
@@ -241,8 +241,8 @@ int main()
 	
 	CHECK_FRAME_SIZE(novell_frame_size, 0,    44);
 	CHECK_FRAME_SIZE(novell_frame_size, 50,   94);
-	CHECK_FRAME_SIZE(novell_frame_size, 1456, 1500);
-	CHECK_FRAME_SIZE(novell_frame_size, 1457, 0);
+	CHECK_FRAME_SIZE(novell_frame_size, 1470, 1514);
+	CHECK_FRAME_SIZE(novell_frame_size, 1471, 0);
 	
 	/* +===================+
 	 * | novell_frame_pack |
@@ -510,8 +510,8 @@ int main()
 	
 	CHECK_FRAME_SIZE(llc_frame_size, 0,    47);
 	CHECK_FRAME_SIZE(llc_frame_size, 50,   97);
-	CHECK_FRAME_SIZE(llc_frame_size, 1453, 1500);
-	CHECK_FRAME_SIZE(llc_frame_size, 1454, 0);
+	CHECK_FRAME_SIZE(llc_frame_size, 1467, 1514);
+	CHECK_FRAME_SIZE(llc_frame_size, 1468, 0);
 	
 	/* +================+
 	 * | llc_frame_pack |
diff --git a/tests/lib/IPXWrapper/Capture/IPX.pm b/tests/lib/IPXWrapper/Capture/IPX.pm
index 6063285..e991851 100644
--- a/tests/lib/IPXWrapper/Capture/IPX.pm
+++ b/tests/lib/IPXWrapper/Capture/IPX.pm
@@ -28,7 +28,7 @@ sub new
 	my ($class, $dev) = @_;
 	
 	my $err;
-	my $pcap = Net::Pcap::pcap_open_live($dev, 1500, 0, 1, \$err)
+	my $pcap = Net::Pcap::pcap_open_live($dev, 2000, 0, 1, \$err)
 		or die("Cannot open device $dev: $err");
 	
 	return bless(\$pcap, $class);
diff --git a/tests/lib/IPXWrapper/Capture/IPXLLC.pm b/tests/lib/IPXWrapper/Capture/IPXLLC.pm
index a7f2607..462f52a 100644
--- a/tests/lib/IPXWrapper/Capture/IPXLLC.pm
+++ b/tests/lib/IPXWrapper/Capture/IPXLLC.pm
@@ -28,7 +28,7 @@ sub new
 	my ($class, $dev) = @_;
 	
 	my $err;
-	my $pcap = Net::Pcap::pcap_open_live($dev, 1500, 0, 1, \$err)
+	my $pcap = Net::Pcap::pcap_open_live($dev, 2000, 0, 1, \$err)
 		or die("Cannot open device $dev: $err");
 	
 	return bless(\$pcap, $class);
diff --git a/tests/lib/IPXWrapper/Capture/IPXNovell.pm b/tests/lib/IPXWrapper/Capture/IPXNovell.pm
index bd5cbf6..656f190 100644
--- a/tests/lib/IPXWrapper/Capture/IPXNovell.pm
+++ b/tests/lib/IPXWrapper/Capture/IPXNovell.pm
@@ -28,7 +28,7 @@ sub new
 	my ($class, $dev) = @_;
 	
 	my $err;
-	my $pcap = Net::Pcap::pcap_open_live($dev, 1500, 0, 1, \$err)
+	my $pcap = Net::Pcap::pcap_open_live($dev, 2000, 0, 1, \$err)
 		or die("Cannot open device $dev: $err");
 	
 	return bless(\$pcap, $class);
diff --git a/tests/lib/IPXWrapper/Util.pm b/tests/lib/IPXWrapper/Util.pm
index cfd8f3e..b4323f4 100644
--- a/tests/lib/IPXWrapper/Util.pm
+++ b/tests/lib/IPXWrapper/Util.pm
@@ -55,12 +55,14 @@ sub run_remote_cmd
 	note(join(" ", @command));
 	
 	my $output = "";
-	IPC::Run::run(\@command, ">&" => \$output)
-		or die("Failure running $exe_name:\n$output");
+	my $ok = IPC::Run::run(\@command, ">&" => \$output);
 	
 	# Oh line endings, how do I hate thee? Let me count the ways.
 	$output =~ s/\r//g;
 	
+	die("Failure running $exe_name:\n$output")
+		unless($ok);
+	
 	return $output;
 }
 
diff --git a/tools/ipx-recv.c b/tools/ipx-recv.c
index 320a1f9..d21b564 100644
--- a/tools/ipx-recv.c
+++ b/tools/ipx-recv.c
@@ -28,7 +28,7 @@
 #include "tools.h"
 
 const int MAX_SOCKETS = 32;
-const int BUFSIZE     = 64;
+const int BUFSIZE     = 2048;
 
 static void usage(const char *argv0)
 {
diff --git a/tools/ipx-send.c b/tools/ipx-send.c
index 8335201..5228d75 100644
--- a/tools/ipx-send.c
+++ b/tools/ipx-send.c
@@ -43,7 +43,7 @@ int main(int argc, char **argv)
 	BOOL reuse = FALSE;
 	
 	int opt;
-	while((opt = getopt(argc, argv, "n:h:s:t:d:br")) != -1)
+	while((opt = getopt(argc, argv, "n:h:s:t:d:l:br")) != -1)
 	{
 		if(opt == 'n')
 		{
@@ -65,6 +65,13 @@ int main(int argc, char **argv)
 		{
 			data = optarg;
 		}
+		else if(opt == 'l')
+		{
+			int len = atoi(optarg);
+			assert((data = malloc(len)) != NULL);
+			
+			memset((char*)(data), 0xAA, len);
+		}
 		else if(opt == 'b')
 		{
 			bcast = TRUE;
@@ -87,6 +94,7 @@ int main(int argc, char **argv)
 			"[-s <local socket number>]\n"
 			"[-t <packet type>]\n"
 			"[-d <payload>]\n"
+			"[-l <payload length>]\n"
 			"[-b (enable SO_BROADCAST)]\n"
 			"[-r (enable SO_REUSEADDR)]\n"
 			"<remote network number>\n"
@@ -132,7 +140,14 @@ int main(int argc, char **argv)
 		printf("Bound to local address: %s\n", formatted_addr);
 	}
 	
-	assert(sendto(sock, data, strlen(data), 0, (struct sockaddr*)(&remote_addr), sizeof(remote_addr)) == strlen(data));
+	int sr = sendto(sock, data, strlen(data), 0, (struct sockaddr*)(&remote_addr), sizeof(remote_addr));
+	if(sr == -1)
+	{
+		fprintf(stderr, "sendto: %u\n", (unsigned int)(WSAGetLastError()));
+		return 1;
+	}
+	
+	assert(sr == strlen(data));
 	
 	closesocket(sock);