fw: Add default HopLimit to Interest when missing

Refs: #5171
Change-Id: I5973811b5ca7c7cf5ff344872afa51b253b9cae8
diff --git a/nfd.conf.sample.in b/nfd.conf.sample.in
index 00f3bf6..09aa5c0 100644
--- a/nfd.conf.sample.in
+++ b/nfd.conf.sample.in
@@ -1,4 +1,4 @@
-; The general section contains settings of nfd process.
+; The general section contains global settings for the nfd process.
 general
 {
   ; Specify a user and/or group for NFD to drop privileges to
@@ -42,14 +42,23 @@
   ; Forwarder INFO
 }
 
+; The forwarder section contains settings that affect the core forwarding behavior of nfd.
+forwarder
+{
+  ; Specify the HopLimit that is added to incoming Interests without a HopLimit element.
+  ; A value of 0 disables adding the HopLimit.
+  ; Must be between 0 and 255. The default is 0.
+  default_hop_limit 0
+}
+
 ; The tables section configures the CS, PIT, FIB, Strategy Choice, and Measurements
 tables
 {
-  ; ContentStore size limit in number of packets
-  ; default is 65536, about 500MB with 8KB packet size
+  ; Content Store capacity limit in number of packets.
+  ; The default is 65536, equivalent to about 500MB with 8KB packet size.
   cs_max_packets 65536
 
-  ; Set the CS replacement policy.
+  ; Content Store replacement policy.
   ; Available policies are: priority_fifo, lru
   cs_policy lru