diff --git a/doc/configuration.txt b/doc/configuration.txt
index 50f82e5..84fc9c9 100644
--- a/doc/configuration.txt
+++ b/doc/configuration.txt
@@ -381,8 +381,10 @@
    - nosepoll
    - nosplice
    - spread-checks
+   - tune.bufsize
    - tune.maxaccept
    - tune.maxpollevents
+   - tune.maxrewrite
   
  * Debugging
    - debug
@@ -557,6 +559,16 @@
   some randomness in the check interval between 0 and +/- 50%. A value between
   2 and 5 seems to show good results. The default value remains at 0.
 
+tune.bufsize <number>
+  Sets the buffer size to this size (in bytes). Lower values allow more
+  sessions to coexist in the same amount of RAM, and higher values allow some
+  applications with very large cookies to work. The default value is 16384 and
+  can be changed at build time. It is strongly recommended not to change this
+  from the default value, as very low values will break some services such as
+  statistics, and values larger than default size will increase memory usage,
+  possibly causing the system to run out of memory. At least the global maxconn
+  parameter should be decreased by the same factor as this one is increased.
+
 tune.maxaccept <number>
   Sets the maximum number of consecutive accepts that a process may perform on
   a single wake up. High values give higher priority to high connection rates,
@@ -574,6 +586,18 @@
   latency at the expense of network bandwidth, and increasing it above 200
   tends to trade latency for slightly increased bandwidth.
 
+tune.maxrewrite <number>
+  Sets the reserved buffer space to this size in bytes. The reserved space is
+  used for header rewriting or appending. The first reads on sockets will never
+  fill more than bufsize-maxrewrite. Historically it has defaulted to half of
+  bufsize, though that does not make much sense since there are rarely large
+  numbers of headers to add. Setting it too high prevents processing of large
+  requests or responses. Setting it too low prevents addition of new headers
+  to already large requests or to POST requests. It is generally wise to set it
+  to about 1024. It is automatically readjusted to half of bufsize if it is
+  larger than that. This means you don't have to worry about it when changing
+  bufsize.
+
 
 3.3. Debugging
 --------------
diff --git a/include/types/global.h b/include/types/global.h
index aefee32..4d349c3 100644
--- a/include/types/global.h
+++ b/include/types/global.h
@@ -79,6 +79,8 @@
 		int maxaccept;     /* max number of consecutive accept() */
 		int options;       /* various tuning options */
 		int recv_enough;   /* how many input bytes at once are "enough" */
+		int bufsize;       /* buffer size in bytes, defaults to BUFSIZE */
+		int maxrewrite;    /* buffer max rewrite size in bytes, defaults to MAXREWRITE */
 	} tune;
 	struct listener stats_sock; /* unix socket listener for statistics */
 	struct proxy *stats_fe;     /* the frontend holding the stats settings */
diff --git a/src/buffers.c b/src/buffers.c
index 55b7963..a20f3f4 100644
--- a/src/buffers.c
+++ b/src/buffers.c
@@ -17,6 +17,7 @@
 #include <common/config.h>
 #include <common/memory.h>
 #include <proto/buffers.h>
+#include <types/global.h>
 
 struct pool_head *pool2_buffer;
 
@@ -24,7 +25,7 @@
 /* perform minimal intializations, report 0 in case of error, 1 if OK. */
 int init_buffer()
 {
-	pool2_buffer = create_pool("buffer", sizeof(struct buffer) + BUFSIZE, MEM_F_SHARED);
+	pool2_buffer = create_pool("buffer", sizeof(struct buffer) + global.tune.bufsize, MEM_F_SHARED);
 	return pool2_buffer != NULL;
 }
 
diff --git a/src/cfgparse.c b/src/cfgparse.c
index a6b9f07..3828812 100644
--- a/src/cfgparse.c
+++ b/src/cfgparse.c
@@ -445,6 +445,26 @@
 		}
 		global.tune.maxaccept = atol(args[1]);
 	}
+	else if (!strcmp(args[0], "tune.bufsize")) {
+		if (*(args[1]) == 0) {
+			Alert("parsing [%s:%d] : '%s' expects an integer argument.\n", file, linenum, args[0]);
+			err_code |= ERR_ALERT | ERR_FATAL;
+			goto out;
+		}
+		global.tune.bufsize = atol(args[1]);
+		if (global.tune.maxrewrite >= global.tune.bufsize / 2)
+			global.tune.maxrewrite = global.tune.bufsize / 2;
+	}
+	else if (!strcmp(args[0], "tune.maxrewrite")) {
+		if (*(args[1]) == 0) {
+			Alert("parsing [%s:%d] : '%s' expects an integer argument.\n", file, linenum, args[0]);
+			err_code |= ERR_ALERT | ERR_FATAL;
+			goto out;
+		}
+		global.tune.maxrewrite = atol(args[1]);
+		if (global.tune.maxrewrite >= global.tune.bufsize / 2)
+			global.tune.maxrewrite = global.tune.bufsize / 2;
+	}
 	else if (!strcmp(args[0], "uid")) {
 		if (global.uid != 0) {
 			Alert("parsing [%s:%d] : user/uid already specified. Continuing.\n", file, linenum);
@@ -3482,13 +3502,13 @@
 			goto out;
 		}
 
-		if (stat.st_size <= BUFSIZE) {
+		if (stat.st_size <= global.tune.bufsize) {
 			errlen = stat.st_size;
 		} else {
 			Warning("parsing [%s:%d] : custom error message file <%s> larger than %d bytes. Truncating.\n",
-				file, linenum, args[2], BUFSIZE);
+				file, linenum, args[2], global.tune.bufsize);
 			err_code |= ERR_WARN;
-			errlen = BUFSIZE;
+			errlen = global.tune.bufsize;
 		}
 
 		err = malloc(errlen); /* malloc() must succeed during parsing */
diff --git a/src/client.c b/src/client.c
index 92baefc..76ea122 100644
--- a/src/client.c
+++ b/src/client.c
@@ -384,7 +384,7 @@
 		if ((s->req = pool_alloc2(pool2_buffer)) == NULL)
 			goto out_fail_req; /* no memory */
 
-		s->req->size = BUFSIZE;
+		s->req->size = global.tune.bufsize;
 		buffer_init(s->req);
 		s->req->prod = &s->si[0];
 		s->req->cons = &s->si[1];
@@ -393,7 +393,7 @@
 		s->req->flags |= BF_READ_ATTACHED; /* the producer is already connected */
 
 		if (p->mode == PR_MODE_HTTP) { /* reserve some space for header rewriting */
-			s->req->max_len -= MAXREWRITE;
+			s->req->max_len -= global.tune.maxrewrite;
 			s->req->flags |= BF_READ_DONTWAIT; /* one read is usually enough */
 		}
 
@@ -411,7 +411,7 @@
 		if ((s->rep = pool_alloc2(pool2_buffer)) == NULL)
 			goto out_fail_rep; /* no memory */
 
-		s->rep->size = BUFSIZE;
+		s->rep->size = global.tune.bufsize;
 		buffer_init(s->rep);
 		s->rep->prod = &s->si[1];
 		s->rep->cons = &s->si[0];
diff --git a/src/haproxy.c b/src/haproxy.c
index 09f8288..dd03e32 100644
--- a/src/haproxy.c
+++ b/src/haproxy.c
@@ -122,7 +122,11 @@
 				 .mode = 0,
 			 }
 		 }
-	}
+	},
+	.tune = {
+		.bufsize = BUFSIZE,
+		.maxrewrite = MAXREWRITE,
+	},
 	/* others NULL OK */
 };
 
@@ -177,7 +181,10 @@
 #ifdef BUILD_OPTIONS
 	       "\n  OPTIONS = " BUILD_OPTIONS
 #endif
-	       "\n\n");
+	       "\n\nDefault settings :"
+	       "\n  maxconn = %d, bufsize = %d, maxrewrite = %d, maxpollevents = %d"
+	       "\n\n",
+	       DEFAULT_MAXCONN, BUFSIZE, MAXREWRITE, MAX_POLL_EVENTS);
 }
 
 /*
@@ -604,6 +611,9 @@
 	if (global.tune.recv_enough == 0)
 		global.tune.recv_enough = MIN_RECV_AT_ONCE_ENOUGH;
 
+	if (global.tune.maxrewrite >= global.tune.bufsize / 2)
+		global.tune.maxrewrite = global.tune.bufsize / 2;
+
 	if (arg_mode & (MODE_DEBUG | MODE_FOREGROUND)) {
 		/* command line debug mode inhibits configuration mode */
 		global.mode &= ~(MODE_DAEMON | MODE_QUIET);
diff --git a/src/proto_uxst.c b/src/proto_uxst.c
index 0cd6a35..c811f64 100644
--- a/src/proto_uxst.c
+++ b/src/proto_uxst.c
@@ -482,7 +482,7 @@
 		if ((s->req = pool_alloc2(pool2_buffer)) == NULL)
 			goto out_free_task;
 
-		s->req->size = BUFSIZE;
+		s->req->size = global.tune.bufsize;
 		buffer_init(s->req);
 		s->req->prod = &s->si[0];
 		s->req->cons = &s->si[1];
@@ -499,7 +499,7 @@
 		if ((s->rep = pool_alloc2(pool2_buffer)) == NULL)
 			goto out_free_req;
 
-		s->rep->size = BUFSIZE;
+		s->rep->size = global.tune.bufsize;
 		buffer_init(s->rep);
 
 		s->rep->prod = &s->si[1];
diff --git a/src/session.c b/src/session.c
index 23c4409..f0c2d86 100644
--- a/src/session.c
+++ b/src/session.c
@@ -330,7 +330,7 @@
 		}
 	}
 	else {
-		buffer_set_rlim(rep, req->size - MAXREWRITE); /* rewrite needed */
+		buffer_set_rlim(rep, req->size - global.tune.maxrewrite); /* rewrite needed */
 		s->txn.rsp.msg_state = HTTP_MSG_RPBEFORE;
 		/* reset hdr_idx which was already initialized by the request.
 		 * right now, the http parser does it.