diff --git a/src/defs.h b/src/defs.h
index 0d7a11f..40f119b 100644
--- a/src/defs.h
+++ b/src/defs.h
@@ -338,7 +338,7 @@
    struct import *import;
    struct licence licence;
    char *dedup;
-   int child_serial;
+   unsigned char child_serial;
    int pos;
 
 #ifdef HAVE_TRE
diff --git a/src/import.c b/src/import.c
index 254a884..7e8e185 100644
--- a/src/import.c
+++ b/src/import.c
@@ -26,7 +26,7 @@
    struct counters counters;
 
 
-   init_session_data(sdata, cfg);
+   init_session_data(sdata, 0, cfg);
 
    if(data->import->extra_recipient){
       snprintf(sdata->rcptto[0], SMALLBUFSIZE-1, "%s", data->import->extra_recipient);
diff --git a/src/misc.c b/src/misc.c
index 9643acd..29a1c25 100644
--- a/src/misc.c
+++ b/src/misc.c
@@ -331,13 +331,13 @@
 }
 
 
-void create_id(char *id, unsigned char server_id){
+void create_id(char *id, unsigned char server_id, unsigned char child_serial){
    int i;
    unsigned char buf[RND_STR_LEN/2];
 
    memset(id, 0, SMALLBUFSIZE);
 
-   get_random_bytes(buf, RND_STR_LEN/2, server_id);
+   get_random_bytes(buf, RND_STR_LEN/2, server_id, child_serial);
 
    for(i=0; i < RND_STR_LEN/2; i++){
       sprintf(id, "%02x", buf[i]);
@@ -351,7 +351,7 @@
  * reading from pool
  */
 
-int get_random_bytes(unsigned char *buf, int len, unsigned char server_id){
+int get_random_bytes(unsigned char *buf, int len, unsigned char server_id, unsigned char child_serial){
    int fd, ret=0;
    struct taia now;
    char nowpack[TAIA_PACK];
@@ -367,8 +367,9 @@
    if(fd == -1) return ret;
 
    *(buf + 12) = server_id;
+   *(buf + 13) = child_serial;
 
-   if(readFromEntropyPool(fd, buf+12+1, len-12-1) != len-12-1){
+   if(readFromEntropyPool(fd, buf+13+1, len-13-1) != len-13-1){
       syslog(LOG_PRIORITY, "%s: %s", ERR_CANNOT_READ_FROM_POOL, RANDOM_POOL);
    }
    
@@ -544,13 +545,13 @@
 }
 
 
-void init_session_data(struct session_data *sdata, struct config *cfg){
+void init_session_data(struct session_data *sdata, unsigned char child_serial, struct config *cfg){
    int i;
 
 
    sdata->fd = -1;
 
-   create_id(&(sdata->ttmpfile[0]), cfg->server_id);
+   create_id(&(sdata->ttmpfile[0]), cfg->server_id, child_serial);
    unlink(sdata->ttmpfile);
 
    snprintf(sdata->filename, SMALLBUFSIZE-1, "%s", sdata->ttmpfile);
diff --git a/src/misc.h b/src/misc.h
index ff58cdc..c4a3f38 100644
--- a/src/misc.h
+++ b/src/misc.h
@@ -28,8 +28,8 @@
 int trimBuffer(char *s);
 int extractEmail(char *rawmail, char *email);
 void make_random_string(char *buf, int buflen);
-void create_id(char *id, unsigned char server_id);
-int get_random_bytes(unsigned char *buf, int len, unsigned char server_id);
+void create_id(char *id, unsigned char server_id, unsigned char child_serial);
+int get_random_bytes(unsigned char *buf, int len, unsigned char server_id, unsigned char child_serial);
 int readFromEntropyPool(int fd, void *_s, ssize_t n);
 int recvtimeout(int s, char *buf, int len, int timeout);
 int write1(struct net *net, void *buf, int buflen);
@@ -39,7 +39,7 @@
 void write_pid_file(char *pidfile);
 int drop_privileges(struct passwd *pwd);
 
-void init_session_data(struct session_data *sdata, struct config *cfg);
+void init_session_data(struct session_data *sdata, unsigned char child_serial, struct config *cfg);
 int read_from_stdin(struct session_data *sdata);
 void strtolower(char *s);
 
diff --git a/src/piler.c b/src/piler.c
index 1738274..55d7c77 100644
--- a/src/piler.c
+++ b/src/piler.c
@@ -110,7 +110,7 @@
    }
 #endif
 
-   init_session_data(sdata, cfg);
+   init_session_data(sdata, data->child_serial, cfg);
 
    sdata->tot_len = size;
 
@@ -247,6 +247,8 @@
 
    if(cfg.verbosity >= _LOG_DEBUG) syslog(LOG_PRIORITY, "child (pid: %d, serial: %d) started main() working on '%s'", getpid(), ptr->serial, dir);
 
+   data.child_serial = ptr->serial % 255;
+
    while(1){
       if(received_sighup == 1){
          if(cfg.verbosity >= _LOG_DEBUG) syslog(LOG_PRIORITY, "child (pid: %d) caught HUP signal", getpid());
diff --git a/src/pilerexport.c b/src/pilerexport.c
index 92428da..f24bf30 100644
--- a/src/pilerexport.c
+++ b/src/pilerexport.c
@@ -571,7 +571,7 @@
    if(read_key(&cfg)) p_clean_exit(ERR_READING_KEY, 1);
 
 
-   init_session_data(&sdata, &cfg);
+   init_session_data(&sdata, 0, &cfg);
 
 
    if(open_database(&sdata, &cfg) == ERR){
@@ -581,7 +581,7 @@
 
    if(where_condition){
 
-      init_session_data(&sdata2, &cfg);
+      init_session_data(&sdata2, 0, &cfg);
 
       strcpy(cfg.mysqlhost, "127.0.0.1");
       cfg.mysqlport = 9306;
diff --git a/src/pilerimport.c b/src/pilerimport.c
index b648c36..b609f82 100644
--- a/src/pilerimport.c
+++ b/src/pilerimport.c
@@ -76,6 +76,7 @@
    srand(getpid());
 
    data.folder = 0;
+   data.child_serial = 0;
    data.recursive_folder_names = 0;
    data.quiet = 0;
 
diff --git a/src/reindex.c b/src/reindex.c
index b42b589..b1bfe8e 100644
--- a/src/reindex.c
+++ b/src/reindex.c
@@ -234,7 +234,7 @@
    initrules(data.retention_rules);
    initrules(data.folder_rules);
 
-   init_session_data(&sdata, &cfg);
+   init_session_data(&sdata, 0, &cfg);
 
 
    if(open_database(&sdata, &cfg) == ERR){
diff --git a/src/test.c b/src/test.c
index d10d98e..3f22d35 100644
--- a/src/test.c
+++ b/src/test.c
@@ -73,7 +73,7 @@
    load_rules(&sdata, &data, data.folder_rules, SQL_FOLDER_RULE_TABLE);
 
 
-   init_session_data(&sdata, &cfg);
+   init_session_data(&sdata, 0, &cfg);
  
    sdata.delivered = 0;
    sdata.tot_len = st.st_size;
diff --git a/unit_tests/check_digest.c b/unit_tests/check_digest.c
index bab35dc..c7cbffc 100644
--- a/unit_tests/check_digest.c
+++ b/unit_tests/check_digest.c
@@ -86,7 +86,7 @@
          continue;
       }
 
-      init_session_data(&sdata, cfg);
+      init_session_data(&sdata, 0, cfg);
  
       sdata.delivered = 0;
       sdata.tot_len = st.st_size;
diff --git a/unit_tests/check_parser.c b/unit_tests/check_parser.c
index f4606ca..93d349c 100644
--- a/unit_tests/check_parser.c
+++ b/unit_tests/check_parser.c
@@ -66,7 +66,7 @@
          continue;
       }
 
-      init_session_data(&sdata, cfg);
+      init_session_data(&sdata, 0, cfg);
  
       sdata.delivered = 0;
       sdata.tot_len = st.st_size;
diff --git a/unit_tests/check_rules.c b/unit_tests/check_rules.c
index b205308..e007134 100644
--- a/unit_tests/check_rules.c
+++ b/unit_tests/check_rules.c
@@ -113,7 +113,7 @@
          continue;
       }
 
-      init_session_data(&sdata, cfg);
+      init_session_data(&sdata, 0, cfg);
  
       sdata.delivered = 0;
       sdata.tot_len = st.st_size;