diff --git a/src/gb/gprs_ns2_udp.c b/src/gb/gprs_ns2_udp.c
index 0f22458..36f6a97 100644
--- a/src/gb/gprs_ns2_udp.c
+++ b/src/gb/gprs_ns2_udp.c
@@ -368,6 +368,10 @@
 				dscp, rc, errno);
 	}
 
+	/* IPv4: max fragmented payload can be (13 bit) * 8 byte => 65535.
+	 * IPv6: max payload can be 65535 (RFC 2460).
+	 * UDP header = 8 byte */
+	bind->mtu = 65535 - 8;
 	if (result)
 		*result = bind;