diff --git a/gtp/gtp.c b/gtp/gtp.c
index 94c3245..799f8a7 100644
--- a/gtp/gtp.c
+++ b/gtp/gtp.c
@@ -513,6 +513,8 @@
 		qmsg->cbp = cbp;
 		qmsg->type = ntoh8(packet->gtp0.h.type);
 		qmsg->fd = fd;
+		if (pdp) /* echo requests are not pdp-bound */
+			llist_add(&qmsg->entry, &pdp->qmsg_list_req);
 	}
 	gsn->seq_next++;	/* Count up this time */
 	return 0;
@@ -697,6 +699,9 @@
 		qmsg->cbp = NULL;
 		qmsg->type = 0;
 		qmsg->fd = fd;
+		/* No need to add to pdp list here, because even on pdp ctx free
+		   we want to leave messages in queue_resp until timeout to
+		   detect duplicates */
 	}
 	return 0;
 }
diff --git a/gtp/pdp.c b/gtp/pdp.c
index d745916..eaef545 100644
--- a/gtp/pdp.c
+++ b/gtp/pdp.c
@@ -31,6 +31,7 @@
 #include "pdp.h"
 #include "gtp.h"
 #include "lookupa.h"
+#include "queue.h"
 
 /* ***********************************************************
  * Functions related to PDP storage
@@ -156,7 +157,7 @@
 			}
 			/* Default: Generate G-PDU sequence numbers on Tx */
 			(*pdp)->tx_gpdu_seq = true;
-
+			INIT_LLIST_HEAD(&(*pdp)->qmsg_list_req);
 			return 0;
 		}
 	}
@@ -165,7 +166,17 @@
 
 int pdp_freepdp(struct pdp_t *pdp)
 {
+	struct qmsg_t *qmsg, *qmsg2;
 	struct pdp_t *pdpa = pdp->gsn->pdpa;
+	int rc;
+
+	/* Remove all enqueued messages belonging to this pdp from req tx transmit
+	   queue. queue_freemsg will call llist_del(). */
+	llist_for_each_entry_safe(qmsg, qmsg2, &pdp->qmsg_list_req, entry) {
+		if ((rc = queue_freemsg(pdp->gsn->queue_req, qmsg)))
+			LOGP(DLGTP, LOGL_ERROR,
+			     "Failed freeing qmsg from qmsg_list_req during pdp_freepdp()! %d\n", rc);
+	}
 
 	pdp_tiddel(pdp);
 
diff --git a/gtp/pdp.h b/gtp/pdp.h
index d64d394..fdfa824 100644
--- a/gtp/pdp.h
+++ b/gtp/pdp.h
@@ -17,6 +17,7 @@
 #include <netinet/in.h>
 
 #include <osmocom/core/defs.h>
+#include <osmocom/core/linuxlist.h>
 
 struct gsn_t;
 
@@ -241,6 +242,8 @@
 	struct gsn_t *gsn; /* Back pointer to GSN where this pdp ctx belongs to */
 
 	bool tx_gpdu_seq;		/* Transmit (true) or suppress G-PDU sequence numbers */
+
+	struct llist_head qmsg_list_req; /* list of req qmsg_t in retrans queue belonging this pdp ctx */
 };
 
 /* functions related to pdp_t management */
diff --git a/gtp/queue.c b/gtp/queue.c
index ce4713e..4c25913 100644
--- a/gtp/queue.c
+++ b/gtp/queue.c
@@ -172,6 +172,7 @@
 	} else {
 		*qmsg = &queue->qmsga[queue->next];
 		queue_seqset(queue, *qmsg, peer, seq);
+		INIT_LLIST_HEAD(&(*qmsg)->entry);
 		(*qmsg)->state = 1;	/* Space taken */
 		(*qmsg)->this = queue->next;
 		(*qmsg)->next = -1;	/* End of the queue */
@@ -206,6 +207,8 @@
 		return EOF;	/* Not in queue */
 	}
 
+	llist_del(&qmsg->entry);
+
 	queue_seqdel(queue, qmsg);
 
 	if (qmsg->next == -1)	/* Are we the last in queue? */
diff --git a/gtp/queue.h b/gtp/queue.h
index 76cb7be..9b0367b 100644
--- a/gtp/queue.h
+++ b/gtp/queue.h
@@ -17,6 +17,8 @@
 #ifndef _QUEUE_H
 #define _QUEUE_H
 
+#include <osmocom/core/linuxlist.h>
+
 #include "gtp.h"
 
 #define QUEUE_DEBUG 0		/* Print debug information */
@@ -39,6 +41,7 @@
 	int this;		/* Pointer to myself */
 	time_t timeout;		/* When do we retransmit this packet? */
 	int retrans;		/* How many times did we retransmit this? */
+	struct llist_head entry; /* Listed with other qmsg_t belonging to a pdp_t->qmsg_list_req */
 };
 
 struct queue_t {