diff --git a/include/attach.h b/include/attach.h
index e127ae4..599fceb 100644
--- a/include/attach.h
+++ b/include/attach.h
@@ -21,15 +21,7 @@
 #include <stdint.h>
 #include <stddef.h>
 
-struct email_t{
-	char* message;
-	/* From the below values you can say pretty much anything about the 
-	 * message. The line delimiting body and header is left out. The header
-	 * len includes the last \r\n of the header. If header len is zero,
-	 * there was no clear distinction between header and body...
-	 */
-	size_t header_len, body_offset, message_length;
-};
+#include "mail.h"
 
 struct email_t mail_from_text(char* message, size_t length);
 void redetect_body_head(struct email_t* mail);
diff --git a/include/mail.h b/include/mail.h
new file mode 100644
index 0000000..44272fc
--- /dev/null
+++ b/include/mail.h
@@ -0,0 +1,37 @@
+/*
+ * mail.h - Mail editing toolset
+ * The author licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ * 
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+#ifndef MAIL_H
+#define MAIL_H
+
+#include <stdint.h>
+#include <stddef.h>
+
+struct email_t{
+	char* message;
+	/* From the below values you can say pretty much anything about the 
+	 * message. The line delimiting body and header is left out. The header
+	 * len includes the last \r\n of the header. If header len is zero,
+	 * there was no clear distinction between header and body...
+	 */
+	size_t header_len, body_offset, message_length;
+};
+
+int append_header(struct email_t* mail, const char* key, const char* value);
+int append_to_header(struct email_t* mail, const char* pair);
+
+#endif /* MAIL_H */
diff --git a/include/tools.h b/include/tools.h
index 48f7362..0f571f7 100644
--- a/include/tools.h
+++ b/include/tools.h
@@ -20,7 +20,7 @@
 
 #include <stddef.h>
 
-const char* insert_string(char * destination, const char* source, 
+char* insert_string(char * destination, const char* source, 
 	size_t dest_orig_len, size_t offset);
 
 
diff --git a/src/attach.c b/src/attach.c
index 2ca2b5a..585c6b4 100644
--- a/src/attach.c
+++ b/src/attach.c
@@ -19,6 +19,7 @@
 #include "attach.h"
 #include "detect.h"
 #include "config.h"
+#include "mail.h"
 
 #include <string.h>
 #include <stdio.h>
@@ -94,6 +95,10 @@ char* attach_files(char* message, size_t len){
 		return email.message;
 	}
 
+	/* Now we can start the real work! */
+	
+	/* Announce our presence via header */
+	append_header(&email,"X-Mailattached", instance_id);
 	return email.message;
 }
 
diff --git a/src/mail.c b/src/mail.c
new file mode 100644
index 0000000..463d499
--- /dev/null
+++ b/src/mail.c
@@ -0,0 +1,77 @@
+/*
+ * mail.c - Mail editing toolset
+ * The author licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ * 
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+#include "mail.h"
+#include "tools.h"
+
+#include <string.h>
+#include <stddef.h>
+#include <stdint.h>
+#include <stdlib.h>
+
+int append_header(struct email_t* mail, const char* key, const char* value){
+	
+	if(mail == NULL || key == NULL || value == NULL){
+		return -1;
+	}
+	const char* in_between = ": ";
+	size_t len = strlen(key) + strlen(value) + strlen(in_between) + 1;
+	char* buffer = malloc(len);
+	
+	if(buffer == NULL){
+		return -1;
+	}
+	
+	memset(buffer, 0, len);
+	strcat(buffer, key);
+	strcat(buffer, in_between);
+	strcat(buffer, value);
+	if(append_to_header(mail, buffer) < 0){
+		free(buffer);
+		return -1;
+	}
+	
+	free(buffer);
+
+	return 0;
+
+}
+
+
+int append_to_header(struct email_t* mail, const char* pair){
+
+	if(pair == NULL || mail == NULL){
+		return -1;
+	}
+
+	char *buffer = malloc(strlen(pair) + 3);
+	if(buffer == NULL){
+		return -1;
+	}
+	memset(buffer, 0, strlen(pair) + 3);
+	buffer[0] = '\r';
+	buffer[1] = '\n';
+	strcat(buffer, pair);
+
+	mail->message=insert_string(mail->message, buffer, strlen(buffer), 
+		mail->header_len);
+	free(buffer);
+
+	return 0;
+
+}
+
diff --git a/src/network.c b/src/network.c
index e5d3e2f..5a0ee0d 100644
--- a/src/network.c
+++ b/src/network.c
@@ -248,7 +248,8 @@ int init_net(){
 	serveraddr.sin_port = htons((unsigned short)listen_port);
 
 	if (bind(parentfd, (struct sockaddr *) &serveraddr,
-	   sizeof(serveraddr)) < 0) {
+		sizeof(serveraddr)) < 0) {
+		
 		perror("ERROR on binding");
 		return -1;
 	}
diff --git a/src/tools.c b/src/tools.c
index 17b7d41..37054b3 100644
--- a/src/tools.c
+++ b/src/tools.c
@@ -24,7 +24,7 @@
 /* Takes a string destination and inserts at the given point offset the string
  * in source. Really more like a stringcat with shifting the end. 
  * dest_orig_len is without '\0'*/
-const char* insert_string(char * destination, const char* source, 
+char* insert_string(char * destination, const char* source, 
 	size_t dest_orig_len, size_t offset){
 
 	if(source == NULL|| dest_orig_len < offset){