diff --git a/evdns.c b/evdns.c
index aad21e27..26d26b47 100644
--- a/evdns.c
+++ b/evdns.c
@@ -2503,7 +2503,7 @@ int evdns_resolve_ipv6(const char *name, int flags,
 }
 
 struct evdns_request *
-evdns_base_resolve_reverse(struct evdns_base *base, struct in_addr *in, int flags, evdns_callback_type callback, void *ptr) {
+evdns_base_resolve_reverse(struct evdns_base *base, const struct in_addr *in, int flags, evdns_callback_type callback, void *ptr) {
 	char buf[32];
 	struct evdns_request *req;
 	u32 a;
@@ -2521,13 +2521,13 @@ evdns_base_resolve_reverse(struct evdns_base *base, struct in_addr *in, int flag
 	return (req);
 }
 
-int evdns_resolve_reverse(struct in_addr *in, int flags, evdns_callback_type callback, void *ptr) {
+int evdns_resolve_reverse(const struct in_addr *in, int flags, evdns_callback_type callback, void *ptr) {
 	return evdns_base_resolve_reverse(current_base, in, flags, callback, ptr)
 		? 0 : -1;
 }
 
 struct evdns_request *
-evdns_base_resolve_reverse_ipv6(struct evdns_base *base, struct in6_addr *in, int flags, evdns_callback_type callback, void *ptr) {
+evdns_base_resolve_reverse_ipv6(struct evdns_base *base, const struct in6_addr *in, int flags, evdns_callback_type callback, void *ptr) {
 	/* 32 nybbles, 32 periods, "ip6.arpa", NUL. */
 	char buf[73];
 	char *cp;
@@ -2551,7 +2551,7 @@ evdns_base_resolve_reverse_ipv6(struct evdns_base *base, struct in6_addr *in, in
 	return (req);
 }
 
-int evdns_resolve_reverse_ipv6(struct in6_addr *in, int flags, evdns_callback_type callback, void *ptr) {
+int evdns_resolve_reverse_ipv6(const struct in6_addr *in, int flags, evdns_callback_type callback, void *ptr) {
 	return evdns_base_resolve_reverse_ipv6(current_base, in, flags, callback, ptr)
 		? 0 : -1;
 }
diff --git a/include/event2/dns.h b/include/event2/dns.h
index 80cb4772..b9b47e82 100644
--- a/include/event2/dns.h
+++ b/include/event2/dns.h
@@ -365,7 +365,7 @@ struct in6_addr;
   @return an evdns_request object if successful, or NULL if an error occurred.
   @see evdns_resolve_reverse_ipv6(), evdns_cancel_request()
  */
-struct evdns_request *evdns_base_resolve_reverse(struct evdns_base *base, struct in_addr *in, int flags, evdns_callback_type callback, void *ptr);
+struct evdns_request *evdns_base_resolve_reverse(struct evdns_base *base, const struct in_addr *in, int flags, evdns_callback_type callback, void *ptr);
 
 
 /**
@@ -379,7 +379,7 @@ struct evdns_request *evdns_base_resolve_reverse(struct evdns_base *base, struct
   @return an evdns_request object if successful, or NULL if an error occurred.
   @see evdns_resolve_reverse_ipv6(), evdns_cancel_request()
  */
-struct evdns_request *evdns_base_resolve_reverse_ipv6(struct evdns_base *base, struct in6_addr *in, int flags, evdns_callback_type callback, void *ptr);
+struct evdns_request *evdns_base_resolve_reverse_ipv6(struct evdns_base *base, const struct in6_addr *in, int flags, evdns_callback_type callback, void *ptr);
 
 /**
   Cancels a pending DNS resolution request.
diff --git a/include/event2/dns_compat.h b/include/event2/dns_compat.h
index 26932a21..b7ab513f 100644
--- a/include/event2/dns_compat.h
+++ b/include/event2/dns_compat.h
@@ -206,7 +206,7 @@ struct in6_addr;
   @return 0 if successful, or -1 if an error occurred
   @see evdns_resolve_reverse_ipv6()
  */
-int evdns_resolve_reverse(struct in_addr *in, int flags, evdns_callback_type callback, void *ptr);
+int evdns_resolve_reverse(const struct in_addr *in, int flags, evdns_callback_type callback, void *ptr);
 
 /**
   Lookup a PTR record for a given IPv6 address.
@@ -222,7 +222,7 @@ int evdns_resolve_reverse(struct in_addr *in, int flags, evdns_callback_type cal
   @return 0 if successful, or -1 if an error occurred
   @see evdns_resolve_reverse_ipv6()
  */
-int evdns_resolve_reverse_ipv6(struct in6_addr *in, int flags, evdns_callback_type callback, void *ptr);
+int evdns_resolve_reverse_ipv6(const struct in6_addr *in, int flags, evdns_callback_type callback, void *ptr);
 
 /**
   Set the value of a configuration option.