diff --git a/makefile b/makefile
index f649865..cb77f52 100644
--- a/makefile
+++ b/makefile
@@ -42,7 +42,7 @@ snake2camel:
 	}' $(file)
 
 .PHONY: bench
-bench: rfc5424/*_test.go rfc5424/machine.go
+bench: rfc5424/*_test.go rfc5424/machine.go octetcounting/performance_test.go
 	go test -bench=. -benchmem -benchtime=5s ./...
 
 .PHONY: tests
diff --git a/nontransparent/parser.go b/nontransparent/parser.go
index 4eae95d..c587202 100644
--- a/nontransparent/parser.go
+++ b/nontransparent/parser.go
@@ -218,6 +218,9 @@ func NewParser(options ...syslog.ParserOption) syslog.Parser {
 	return m
 }
 
+// WithMaxMessageLength does nothing for this parser
+func (m *machine) WithMaxMessageLength(length int) {}
+
 // HasBestEffort tells whether the receiving parser has best effort mode on or off.
 func (m *machine) HasBestEffort() bool {
 	return m.bestEffort
diff --git a/octetcounting/parser.go b/octetcounting/parser.go
index c1f0c88..a79c668 100644
--- a/octetcounting/parser.go
+++ b/octetcounting/parser.go
@@ -12,19 +12,21 @@ import (
 //
 // Use NewParser function to instantiate one.
 type parser struct {
-	msglen     int64
-	s          Scanner
-	internal   syslog.Machine
-	last       Token
-	stepback   bool // Wheter to retrieve the last token or not
-	bestEffort bool // Best effort mode flag
-	emit       syslog.ParserListener
+	msglen           int64
+	maxMessageLength int
+	s                Scanner
+	internal         syslog.Machine
+	last             Token
+	stepback         bool // Wheter to retrieve the last token or not
+	bestEffort       bool // Best effort mode flag
+	emit             syslog.ParserListener
 }
 
 // NewParser returns a syslog.Parser suitable to parse syslog messages sent with transparent - ie. octet counting (RFC 5425) - framing.
 func NewParser(opts ...syslog.ParserOption) syslog.Parser {
 	p := &parser{
-		emit: func(*syslog.Result) { /* noop */ },
+		emit:             func(*syslog.Result) { /* noop */ },
+		maxMessageLength: 8192, // size as per RFC5425#section-4.3.1
 	}
 
 	for _, opt := range opts {
@@ -41,6 +43,10 @@ func NewParser(opts ...syslog.ParserOption) syslog.Parser {
 	return p
 }
 
+func (p *parser) WithMaxMessageLength(length int) {
+	p.maxMessageLength = length
+}
+
 // HasBestEffort tells whether the receiving parser has best effort mode on or off.
 func (p *parser) HasBestEffort() bool {
 	return p.bestEffort
@@ -64,7 +70,7 @@ func (p *parser) WithListener(f syslog.ParserListener) {
 //
 // It stops parsing when an error regarding RFC 5425 is found.
 func (p *parser) Parse(r io.Reader) {
-	p.s = *NewScanner(r)
+	p.s = *NewScanner(r, p.maxMessageLength)
 	p.run()
 }
 
diff --git a/octetcounting/parser_test.go b/octetcounting/parser_test.go
index 764cd5d..53521b6 100644
--- a/octetcounting/parser_test.go
+++ b/octetcounting/parser_test.go
@@ -12,10 +12,11 @@ import (
 )
 
 type testCase struct {
-	descr    string
-	input    string
-	results  []syslog.Result
-	pResults []syslog.Result
+	descr             string
+	input             string
+	results           []syslog.Result
+	bestEffortResults []syslog.Result
+	maxMessageLength  int
 }
 
 var testCases []testCase
@@ -31,20 +32,20 @@ func getParsingError(col int) error {
 func getTestCases() []testCase {
 	return []testCase{
 		{
-			"empty",
-			"",
-			[]syslog.Result{
+			descr: "empty",
+			input: "",
+			results: []syslog.Result{
 				{Error: fmt.Errorf("found %s, expecting a %s", EOF, MSGLEN)},
 			},
-			[]syslog.Result{
+			bestEffortResults: []syslog.Result{
 				{Error: fmt.Errorf("found %s, expecting a %s", EOF, MSGLEN)},
 			},
 		},
 		{
-			"1st ok/2nd mf", // mf means malformed syslog message
-			"16 <1>1 - - - - - -17 <2>12 A B C D E -",
+			descr: "1st ok/2nd mf", // mf means malformed syslog message
+			input: "16 <1>1 - - - - - -17 <2>12 A B C D E -",
 			// results w/o best effort
-			[]syslog.Result{
+			results: []syslog.Result{
 				{
 					Message: (&rfc5424.SyslogMessage{}).SetPriority(1).SetVersion(1),
 				},
@@ -53,7 +54,7 @@ func getTestCases() []testCase {
 				},
 			},
 			// results with best effort
-			[]syslog.Result{
+			bestEffortResults: []syslog.Result{
 				{
 					Message: (&rfc5424.SyslogMessage{}).SetPriority(1).SetVersion(1),
 				},
@@ -64,10 +65,10 @@ func getTestCases() []testCase {
 			},
 		},
 		{
-			"1st ok/2nd ko", // ko means wrong token
-			"16 <1>1 - - - - - -xaaa",
+			descr: "1st ok/2nd ko", // ko means wrong token
+			input: "16 <1>1 - - - - - -xaaa",
 			// results w/o best effort
-			[]syslog.Result{
+			results: []syslog.Result{
 				{
 					Message: (&rfc5424.SyslogMessage{}).SetPriority(1).SetVersion(1),
 				},
@@ -76,7 +77,7 @@ func getTestCases() []testCase {
 				},
 			},
 			// results with best effort
-			[]syslog.Result{
+			bestEffortResults: []syslog.Result{
 				{
 					Message: (&rfc5424.SyslogMessage{}).SetPriority(1).SetVersion(1),
 				},
@@ -86,16 +87,16 @@ func getTestCases() []testCase {
 			},
 		},
 		{
-			"1st ml/2nd ko",
-			"16 <1>1 A B C D E -xaaa",
+			descr: "1st ml/2nd ko",
+			input: "16 <1>1 A B C D E -xaaa",
 			// results w/o best effort
-			[]syslog.Result{
+			results: []syslog.Result{
 				{
 					Error: getTimestampError(5),
 				},
 			},
 			// results with best effort
-			[]syslog.Result{
+			bestEffortResults: []syslog.Result{
 				{
 					Message: (&rfc5424.SyslogMessage{}).SetPriority(1).SetVersion(1),
 					Error:   getTimestampError(5),
@@ -106,10 +107,10 @@ func getTestCases() []testCase {
 			},
 		},
 		{
-			"1st ok//utf8",
-			"23 <1>1 - - - - - - hellø", // msglen MUST be the octet count
+			descr: "1st ok//utf8",
+			input: "23 <1>1 - - - - - - hellø", // msglen MUST be the octet count
 			//results w/o best effort
-			[]syslog.Result{
+			results: []syslog.Result{
 				{
 					Message: (&rfc5424.SyslogMessage{}).
 						SetPriority(1).
@@ -118,7 +119,7 @@ func getTestCases() []testCase {
 				},
 			},
 			// results with best effort
-			[]syslog.Result{
+			bestEffortResults: []syslog.Result{
 				{
 					Message: (&rfc5424.SyslogMessage{}).
 						SetPriority(1).
@@ -128,16 +129,16 @@ func getTestCases() []testCase {
 			},
 		},
 		{
-			"1st ko//incomplete SYSLOGMSG",
-			"16 <1>1",
+			descr: "1st ko//incomplete SYSLOGMSG",
+			input: "16 <1>1",
 			// results w/o best effort
-			[]syslog.Result{
+			results: []syslog.Result{
 				{
 					Error: fmt.Errorf(`found %s after "%s", expecting a %s containing %d octets`, EOF, "<1>1", SYSLOGMSG, 16),
 				},
 			},
 			// results with best effort
-			[]syslog.Result{
+			bestEffortResults: []syslog.Result{
 				{
 					Message: (&rfc5424.SyslogMessage{}).SetPriority(1).SetVersion(1),
 					Error:   getParsingError(4),
@@ -146,42 +147,42 @@ func getTestCases() []testCase {
 			},
 		},
 		{
-			"1st ko//missing WS found ILLEGAL",
-			"16<1>1",
+			descr: "1st ko//missing WS found ILLEGAL",
+			input: "16<1>1",
 			// results w/o best effort
-			[]syslog.Result{
+			results: []syslog.Result{
 				{
 					Error: fmt.Errorf("found %s, expecting a %s", Token{ILLEGAL, []byte("<")}, WS),
 				},
 			},
 			// results with best effort
-			[]syslog.Result{
+			bestEffortResults: []syslog.Result{
 				{
 					Error: fmt.Errorf("found %s, expecting a %s", Token{ILLEGAL, []byte("<")}, WS),
 				},
 			},
 		},
 		{
-			"1st ko//missing WS found EOF",
-			"1",
+			descr: "1st ko//missing WS found EOF",
+			input: "1",
 			// results w/o best effort
-			[]syslog.Result{
+			results: []syslog.Result{
 				{
 					Error: fmt.Errorf("found %s, expecting a %s", EOF, WS),
 				},
 			},
 			// results with best effort
-			[]syslog.Result{
+			bestEffortResults: []syslog.Result{
 				{
 					Error: fmt.Errorf("found %s, expecting a %s", EOF, WS),
 				},
 			},
 		},
 		{
-			"1st ok/2nd ok/3rd ok",
-			"48 <1>1 2003-10-11T22:14:15.003Z host.local - - - -25 <3>1 - host.local - - - -38 <2>1 - host.local su - - - κόσμε",
+			descr: "1st ok/2nd ok/3rd ok",
+			input: "48 <1>1 2003-10-11T22:14:15.003Z host.local - - - -25 <3>1 - host.local - - - -38 <2>1 - host.local su - - - κόσμε",
 			// results w/o best effort
-			[]syslog.Result{
+			results: []syslog.Result{
 				{
 					Message: (&rfc5424.SyslogMessage{}).
 						SetPriority(1).
@@ -205,7 +206,7 @@ func getTestCases() []testCase {
 				},
 			},
 			// results with best effort
-			[]syslog.Result{
+			bestEffortResults: []syslog.Result{
 				{
 					Message: (&rfc5424.SyslogMessage{}).
 						SetPriority(1).
@@ -230,10 +231,10 @@ func getTestCases() []testCase {
 			},
 		},
 		{
-			"1st ok/2nd mf/3rd ok", // mf means malformed syslog message
-			"16 <1>1 - - - - - -17 <2>12 A B C D E -16 <1>1 - - - - - -",
+			descr: "1st ok/2nd mf/3rd ok", // mf means malformed syslog message
+			input: "16 <1>1 - - - - - -17 <2>12 A B C D E -16 <1>1 - - - - - -",
 			// results w/o best effort
-			[]syslog.Result{
+			results: []syslog.Result{
 				{
 					Message: (&rfc5424.SyslogMessage{}).SetPriority(1).SetVersion(1),
 				},
@@ -242,7 +243,7 @@ func getTestCases() []testCase {
 				},
 			},
 			// results with best effort
-			[]syslog.Result{
+			bestEffortResults: []syslog.Result{
 				{
 					Message: (&rfc5424.SyslogMessage{}).SetPriority(1).SetVersion(1),
 				},
@@ -256,8 +257,8 @@ func getTestCases() []testCase {
 			},
 		},
 		{
-			"1st ok//max",
-			fmt.Sprintf(
+			descr: "1st ok//max",
+			input: fmt.Sprintf(
 				"8192 <%d>%d %s %s %s %s %s - %s",
 				syslogtesting.MaxPriority,
 				syslogtesting.MaxVersion,
@@ -269,7 +270,7 @@ func getTestCases() []testCase {
 				string(syslogtesting.MaxMessage),
 			),
 			// results w/o best effort
-			[]syslog.Result{
+			results: []syslog.Result{
 				{
 					Message: (&rfc5424.SyslogMessage{}).
 						SetPriority(syslogtesting.MaxPriority).
@@ -283,7 +284,7 @@ func getTestCases() []testCase {
 				},
 			},
 			// results with best effort
-			[]syslog.Result{
+			bestEffortResults: []syslog.Result{
 				{
 					Message: (&rfc5424.SyslogMessage{}).
 						SetPriority(syslogtesting.MaxPriority).
@@ -298,8 +299,51 @@ func getTestCases() []testCase {
 			},
 		},
 		{
-			"1st ok/2nd ok//max/max",
-			fmt.Sprintf(
+			descr: "1st ok//longer-max",
+			input: fmt.Sprintf(
+				"65529 <%d>%d %s %s %s %s %s - %s",
+				syslogtesting.MaxPriority,
+				syslogtesting.MaxVersion,
+				syslogtesting.MaxRFC3339MicroTimestamp,
+				string(syslogtesting.MaxHostname),
+				string(syslogtesting.MaxAppname),
+				string(syslogtesting.MaxProcID),
+				string(syslogtesting.MaxMsgID),
+				string(syslogtesting.LongerMaxMessage),
+			),
+			// results w/o best effort
+			results: []syslog.Result{
+				{
+					Message: (&rfc5424.SyslogMessage{}).
+						SetPriority(syslogtesting.MaxPriority).
+						SetVersion(syslogtesting.MaxVersion).
+						SetTimestamp(syslogtesting.MaxRFC3339MicroTimestamp).
+						SetHostname(string(syslogtesting.MaxHostname)).
+						SetAppname(string(syslogtesting.MaxAppname)).
+						SetProcID(string(syslogtesting.MaxProcID)).
+						SetMsgID(string(syslogtesting.MaxMsgID)).
+						SetMessage(string(syslogtesting.LongerMaxMessage)),
+				},
+			},
+			// results with best effort
+			bestEffortResults: []syslog.Result{
+				{
+					Message: (&rfc5424.SyslogMessage{}).
+						SetPriority(syslogtesting.MaxPriority).
+						SetVersion(syslogtesting.MaxVersion).
+						SetTimestamp(syslogtesting.MaxRFC3339MicroTimestamp).
+						SetHostname(string(syslogtesting.MaxHostname)).
+						SetAppname(string(syslogtesting.MaxAppname)).
+						SetProcID(string(syslogtesting.MaxProcID)).
+						SetMsgID(string(syslogtesting.MaxMsgID)).
+						SetMessage(string(syslogtesting.LongerMaxMessage)),
+				},
+			},
+			maxMessageLength: 65529,
+		},
+		{
+			descr: "1st ok/2nd ok//max/max",
+			input: fmt.Sprintf(
 				"8192 <%d>%d %s %s %s %s %s - %s8192 <%d>%d %s %s %s %s %s - %s",
 				syslogtesting.MaxPriority,
 				syslogtesting.MaxVersion,
@@ -319,7 +363,7 @@ func getTestCases() []testCase {
 				string(syslogtesting.MaxMessage),
 			),
 			// results w/o best effort
-			[]syslog.Result{
+			results: []syslog.Result{
 				{
 					Message: (&rfc5424.SyslogMessage{}).
 						SetPriority(syslogtesting.MaxPriority).
@@ -344,7 +388,7 @@ func getTestCases() []testCase {
 				},
 			},
 			// results with best effort
-			[]syslog.Result{
+			bestEffortResults: []syslog.Result{
 				{
 					Message: (&rfc5424.SyslogMessage{}).
 						SetPriority(syslogtesting.MaxPriority).
@@ -370,8 +414,81 @@ func getTestCases() []testCase {
 			},
 		},
 		{
-			"1st ok/2nd ok/3rd ok//max/no/max",
-			fmt.Sprintf(
+			descr: "1st ok/2nd ok//longer-max/longer-max",
+			input: fmt.Sprintf(
+				"65529 <%d>%d %s %s %s %s %s - %s65529 <%d>%d %s %s %s %s %s - %s",
+				syslogtesting.MaxPriority,
+				syslogtesting.MaxVersion,
+				syslogtesting.MaxRFC3339MicroTimestamp,
+				string(syslogtesting.MaxHostname),
+				string(syslogtesting.MaxAppname),
+				string(syslogtesting.MaxProcID),
+				string(syslogtesting.MaxMsgID),
+				string(syslogtesting.LongerMaxMessage),
+				syslogtesting.MaxPriority,
+				syslogtesting.MaxVersion,
+				syslogtesting.MaxRFC3339MicroTimestamp,
+				string(syslogtesting.MaxHostname),
+				string(syslogtesting.MaxAppname),
+				string(syslogtesting.MaxProcID),
+				string(syslogtesting.MaxMsgID),
+				string(syslogtesting.LongerMaxMessage),
+			),
+			// results w/o best effort
+			results: []syslog.Result{
+				{
+					Message: (&rfc5424.SyslogMessage{}).
+						SetPriority(syslogtesting.MaxPriority).
+						SetVersion(syslogtesting.MaxVersion).
+						SetTimestamp(syslogtesting.MaxRFC3339MicroTimestamp).
+						SetHostname(string(syslogtesting.MaxHostname)).
+						SetAppname(string(syslogtesting.MaxAppname)).
+						SetProcID(string(syslogtesting.MaxProcID)).
+						SetMsgID(string(syslogtesting.MaxMsgID)).
+						SetMessage(string(syslogtesting.LongerMaxMessage)),
+				},
+				{
+					Message: (&rfc5424.SyslogMessage{}).
+						SetPriority(syslogtesting.MaxPriority).
+						SetVersion(syslogtesting.MaxVersion).
+						SetTimestamp(syslogtesting.MaxRFC3339MicroTimestamp).
+						SetHostname(string(syslogtesting.MaxHostname)).
+						SetAppname(string(syslogtesting.MaxAppname)).
+						SetProcID(string(syslogtesting.MaxProcID)).
+						SetMsgID(string(syslogtesting.MaxMsgID)).
+						SetMessage(string(syslogtesting.LongerMaxMessage)),
+				},
+			},
+			// results with best effort
+			bestEffortResults: []syslog.Result{
+				{
+					Message: (&rfc5424.SyslogMessage{}).
+						SetPriority(syslogtesting.MaxPriority).
+						SetVersion(syslogtesting.MaxVersion).
+						SetTimestamp(syslogtesting.MaxRFC3339MicroTimestamp).
+						SetHostname(string(syslogtesting.MaxHostname)).
+						SetAppname(string(syslogtesting.MaxAppname)).
+						SetProcID(string(syslogtesting.MaxProcID)).
+						SetMsgID(string(syslogtesting.MaxMsgID)).
+						SetMessage(string(syslogtesting.LongerMaxMessage)),
+				},
+				{
+					Message: (&rfc5424.SyslogMessage{}).
+						SetPriority(syslogtesting.MaxPriority).
+						SetVersion(syslogtesting.MaxVersion).
+						SetTimestamp(syslogtesting.MaxRFC3339MicroTimestamp).
+						SetHostname(string(syslogtesting.MaxHostname)).
+						SetAppname(string(syslogtesting.MaxAppname)).
+						SetProcID(string(syslogtesting.MaxProcID)).
+						SetMsgID(string(syslogtesting.MaxMsgID)).
+						SetMessage(string(syslogtesting.LongerMaxMessage)),
+				},
+			},
+			maxMessageLength: 65529,
+		},
+		{
+			descr: "1st ok/2nd ok/3rd ok//max/no/max",
+			input: fmt.Sprintf(
 				"8192 <%d>%d %s %s %s %s %s - %s16 <1>1 - - - - - -8192 <%d>%d %s %s %s %s %s - %s",
 				syslogtesting.MaxPriority,
 				syslogtesting.MaxVersion,
@@ -391,7 +508,7 @@ func getTestCases() []testCase {
 				string(syslogtesting.MaxMessage),
 			),
 			// results w/o best effort
-			[]syslog.Result{
+			results: []syslog.Result{
 				{
 					Message: (&rfc5424.SyslogMessage{}).
 						SetPriority(syslogtesting.MaxPriority).
@@ -419,7 +536,7 @@ func getTestCases() []testCase {
 				},
 			},
 			// results with best effort
-			[]syslog.Result{
+			bestEffortResults: []syslog.Result{
 				{
 					Message: (&rfc5424.SyslogMessage{}).
 						SetPriority(syslogtesting.MaxPriority).
@@ -448,8 +565,8 @@ func getTestCases() []testCase {
 			},
 		},
 		{
-			"1st ml//maxlen gt 8192", // maxlength greather than the buffer size
-			fmt.Sprintf(
+			descr: "1st ml//maxlen gt 8192", // maxlength greather than the buffer size
+			input: fmt.Sprintf(
 				"8193 <%d>%d %s %s %s %s %s - %s",
 				syslogtesting.MaxPriority,
 				syslogtesting.MaxVersion,
@@ -461,7 +578,7 @@ func getTestCases() []testCase {
 				string(syslogtesting.MaxMessage),
 			),
 			// results w/o best effort
-			[]syslog.Result{
+			results: []syslog.Result{
 				{
 					Error: fmt.Errorf(
 						"found %s after \"%s\", expecting a %s containing %d octets",
@@ -482,7 +599,7 @@ func getTestCases() []testCase {
 				},
 			},
 			// results with best effort
-			[]syslog.Result{
+			bestEffortResults: []syslog.Result{
 				{
 					Message: (&rfc5424.SyslogMessage{}).
 						SetPriority(syslogtesting.MaxPriority).
@@ -513,16 +630,16 @@ func getTestCases() []testCase {
 			},
 		},
 		{
-			"1st uf/2nd ok//incomplete SYSLOGMSG/notdetectable",
-			"16 <1>217 <11>1 - - - - - -",
+			descr: "1st uf/2nd ok//incomplete SYSLOGMSG/notdetectable",
+			input: "16 <1>217 <11>1 - - - - - -",
 			// results w/o best effort
-			[]syslog.Result{
+			results: []syslog.Result{
 				{
 					Error: getTimestampError(7),
 				},
 			},
 			// results with best effort
-			[]syslog.Result{
+			bestEffortResults: []syslog.Result{
 				{
 					Message: (&rfc5424.SyslogMessage{}).SetPriority(1).SetVersion(217),
 					Error:   getTimestampError(7),
@@ -540,16 +657,20 @@ func init() {
 }
 
 func TestParse(t *testing.T) {
-	for _, tc := range testCases {
-		tc := tc
-
+	for i := range testCases {
+		tc := testCases[i] // tests could be running in parallel, needs to be scoped.
+		if tc.maxMessageLength == 0 {
+			tc.maxMessageLength = 8192
+		}
 		t.Run(fmt.Sprintf("strict/%s", tc.descr), func(t *testing.T) {
 			t.Parallel()
 
 			res := []syslog.Result{}
-			strictParser := NewParser(syslog.WithListener(func(r *syslog.Result) {
-				res = append(res, *r)
-			}))
+			strictParser := NewParser(
+				syslog.WithListener(func(r *syslog.Result) {
+					res = append(res, *r)
+				}),
+				syslog.WithMaxMessageLength(tc.maxMessageLength))
 			strictParser.Parse(strings.NewReader(tc.input))
 
 			assert.Equal(t, tc.results, res)
@@ -558,12 +679,16 @@ func TestParse(t *testing.T) {
 			t.Parallel()
 
 			res := []syslog.Result{}
-			effortParser := NewParser(syslog.WithBestEffort(), syslog.WithListener(func(r *syslog.Result) {
-				res = append(res, *r)
-			}))
+			effortParser := NewParser(
+				syslog.WithBestEffort(),
+				syslog.WithListener(func(r *syslog.Result) {
+					res = append(res, *r)
+				}),
+				syslog.WithMaxMessageLength(tc.maxMessageLength),
+			)
 			effortParser.Parse(strings.NewReader(tc.input))
 
-			assert.Equal(t, tc.pResults, res)
+			assert.Equal(t, tc.bestEffortResults, res)
 		})
 	}
 }
diff --git a/octetcounting/performance_test.go b/octetcounting/performance_test.go
new file mode 100644
index 0000000..9ba5865
--- /dev/null
+++ b/octetcounting/performance_test.go
@@ -0,0 +1,73 @@
+package octetcounting
+
+import (
+	"bytes"
+	"fmt"
+	"testing"
+
+	"github.com/influxdata/go-syslog/v3"
+	syslogtesting "github.com/influxdata/go-syslog/v3/testing"
+)
+
+// This is here to avoid compiler optimizations that
+// could remove the actual call we are benchmarking
+// during benchmarks
+var benchParseResult syslog.Message
+
+type benchCase struct {
+	input     []byte
+	label     string
+	maxLength int
+}
+
+var benchCases = []benchCase{
+	{
+		label: "Small Message Size",
+		input: []byte("48 <1>1 2003-10-11T22:14:15.003Z host.local - - - -25 <3>1 - host.local - - - -38 <2>1 - host.local su - - - κόσμε"),
+	},
+	{
+		label: "Default Max Message Size",
+		input: []byte(fmt.Sprintf(
+			"8192 <%d>%d %s %s %s %s %s - %s",
+			syslogtesting.MaxPriority,
+			syslogtesting.MaxVersion,
+			syslogtesting.MaxRFC3339MicroTimestamp,
+			string(syslogtesting.MaxHostname),
+			string(syslogtesting.MaxAppname),
+			string(syslogtesting.MaxProcID),
+			string(syslogtesting.MaxMsgID),
+			string(syslogtesting.MaxMessage),
+		)),
+	},
+	{
+		label: "UDP Max Message Size",
+		input: []byte(fmt.Sprintf(
+			"65529 <%d>%d %s %s %s %s %s - %s",
+			syslogtesting.MaxPriority,
+			syslogtesting.MaxVersion,
+			syslogtesting.MaxRFC3339MicroTimestamp,
+			string(syslogtesting.MaxHostname),
+			string(syslogtesting.MaxAppname),
+			string(syslogtesting.MaxProcID),
+			string(syslogtesting.MaxMsgID),
+			string(syslogtesting.LongerMaxMessage),
+		)),
+		maxLength: 65529,
+	},
+}
+
+func BenchmarkParse(b *testing.B) {
+	for _, tc := range benchCases {
+		tc := tc
+		if tc.maxLength == 0 {
+			tc.maxLength = 8192
+		}
+		m := NewParser(syslog.WithBestEffort())
+		b.Run(syslogtesting.RightPad(tc.label, 50), func(b *testing.B) {
+			for i := 0; i < b.N; i++ {
+				reader := bytes.NewReader(tc.input)
+				m.Parse(reader)
+			}
+		})
+	}
+}
diff --git a/octetcounting/scanner.go b/octetcounting/scanner.go
index 015295f..cb1fae0 100644
--- a/octetcounting/scanner.go
+++ b/octetcounting/scanner.go
@@ -7,9 +7,6 @@ import (
 	"strconv"
 )
 
-// size as per RFC5425#section-4.3.1
-var size = 8192
-
 // eof represents a marker byte for the end of the reader
 var eof = byte(0)
 
@@ -37,9 +34,9 @@ type Scanner struct {
 }
 
 // NewScanner returns a pointer to a new instance of Scanner.
-func NewScanner(r io.Reader) *Scanner {
+func NewScanner(r io.Reader, maxLength int) *Scanner {
 	return &Scanner{
-		r: bufio.NewReaderSize(r, size+5), // "8192 " has length 5
+		r: bufio.NewReaderSize(r, maxLength+20), // max uint64 is 19 characters + a space
 	}
 }
 
diff --git a/options.go b/options.go
index 551a0ed..b03ac1f 100644
--- a/options.go
+++ b/options.go
@@ -17,3 +17,11 @@ func WithBestEffort() ParserOption {
 		return p
 	}
 }
+
+// WithMaxMessageLength sets the length of the buffer for octect parsing.
+func WithMaxMessageLength(length int) ParserOption {
+	return func(p Parser) Parser {
+		p.WithMaxMessageLength(length)
+		return p
+	}
+}
diff --git a/syslog.go b/syslog.go
index db628a2..e000794 100644
--- a/syslog.go
+++ b/syslog.go
@@ -15,6 +15,11 @@ type BestEfforter interface {
 	HasBestEffort() bool
 }
 
+// MaxMessager sets the max message size the parser should be able to parse
+type MaxMessager interface {
+	WithMaxMessageLength(length int)
+}
+
 // Machine represent a FSM able to parse an entire syslog message and return it in an structured way.
 type Machine interface {
 	Parse(input []byte) (Message, error)
@@ -29,6 +34,7 @@ type Parser interface {
 	Parse(r io.Reader)
 	WithListener(ParserListener)
 	BestEfforter
+	MaxMessager
 }
 
 // ParserOption represent the type of option setters for Parser instances.
diff --git a/testing/testing.go b/testing/testing.go
index 964ce4e..003b82a 100644
--- a/testing/testing.go
+++ b/testing/testing.go
@@ -57,6 +57,8 @@ var (
 	MaxMsgID = RandomBytes(32)
 	// MaxMessage is a maximum length message that a RFC5424 syslog message can contain when all other fields are at their maximum length.
 	MaxMessage = RandomBytes(7681)
+	// LongerMaxMessage is a maximum length message that a RFC5424 syslog message can contain when all other fields are at their maximum length.
+	LongerMaxMessage = RandomBytes(65018)
 )
 
 // RightPad pads a string with spaces until the given limit, or it cuts the string to the given limit.