diff --git a/ChangeLog b/ChangeLog
index 8004c56..5c8a5ff 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -8,6 +8,9 @@ PLEASE DO NOT E-MAIL INDIVIDUAL DEVELOPERS ABOUT
 ISSUES, AS YOUR E-MAIL MAY BE LOST
 ==========================================================
 
+2020-09-20 Colin Petrie <colin@spakka.net> 
+	* Mask trailing bits in NLRI to correct address representations
+
 2020-06-07 Colin Petrie <colin@spakka.net> v1.6.2
 	* Version fix and make dist
 
diff --git a/bgpdump_lib.c b/bgpdump_lib.c
index d9bb65b..693ad3e 100644
--- a/bgpdump_lib.c
+++ b/bgpdump_lib.c
@@ -1561,6 +1561,7 @@ void process_mp_withdraw(struct mstream *s, struct mp_info *info, struct zebra_i
 }
 
 static int read_prefix_list(struct mstream *s, u_int16_t afi, struct prefix *prefixes, struct zebra_incomplete *incomplete, int is_addp) {
+    u_int8_t maskarray[8] = {0x80, 0xc0, 0xe0, 0xf0, 0xf8, 0xfc, 0xfe, 0xff};
     int count = 0;
     
     while(mstream_can_read(s)) {
@@ -1571,8 +1572,10 @@ static int read_prefix_list(struct mstream *s, u_int16_t afi, struct prefix *pre
         if (is_addp)
             path_id = mstream_getl(s, NULL);
 
-        u_int8_t p_len = mstream_getc(s,NULL); // length in bits
-        u_int8_t p_bytes = (p_len + 7) / 8;
+        u_int8_t p_len = mstream_getc(s,NULL); // prefix length in bits
+        u_int8_t p_bytes = p_len / 8;          // number of complete octets to read
+        u_int8_t p_mask = p_len % 8;           // number of remaining significant bits
+        if (p_mask) p_bytes++;                 // if remaining bits, need to read one more octet
         
         /* Truncated prefix list? */
         if(mstream_can_read(s) < p_bytes) {
@@ -1596,7 +1599,26 @@ static int read_prefix_list(struct mstream *s, u_int16_t afi, struct prefix *pre
             continue;
 
         *prefix = (struct prefix) { .len = p_len, .path_id = path_id };
+
+        /*
+            RFC4271:
+            The Prefix field contains an IP address prefix, followed by
+            the minimum number of trailing bits needed to make the end
+            of the field fall on an octet boundary.  Note that the value
+            of trailing bits is irrelevant.
+
+            Some implementations (including bgpdump.c) pass the address directly
+            into inet_ntoa() without first considering the prefix length.
+            This isn't a problem for anything that works with prefix lengths.
+            But the resulting address visual representation can look wrong.
+            To avoid any confusion, we mask the trailing bits to 0 also.
+        */
+
         mstream_get(s, &prefix->address, p_bytes);
+
+        /* Mask trailing bits to 0 if not aligned on a octet boundary */
+        if (p_mask)
+            ((u_int8_t *)&prefix->address)[p_bytes - 1] &= maskarray[p_mask - 1];
     }
     
     if(count > MAX_PREFIXES) {
diff --git a/test_data/updates.nlri_mask_trailing_bits.gz b/test_data/updates.nlri_mask_trailing_bits.gz
new file mode 100644
index 0000000..d39d49e
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diff --git a/test_expect/updates.nlri_mask_trailing_bits.gz.bgp.gz b/test_expect/updates.nlri_mask_trailing_bits.gz.bgp.gz
new file mode 100644
index 0000000..40bea20
Binary files /dev/null and b/test_expect/updates.nlri_mask_trailing_bits.gz.bgp.gz differ