a client address must be allocated from a connection pool
to live through the keep-alive requests

src/http/modules/ngx_http_realip_module.c

diff --git a/src/http/modules/ngx_http_realip_module.c b/src/http/modules/ngx_http_realip_module.c
index bd5c31c..ffb2028 100644
--- a/src/http/modules/ngx_http_realip_module.c
+++ b/src/http/modules/ngx_http_realip_module.c
@@ -163,10 +163,17 @@
                 return NGX_DECLINED;
             }
 
+            p = ngx_palloc(r->connection->pool, len);
+            if (p == NULL) {
+                return NGX_HTTP_INTERNAL_SERVER_ERROR;
+            }
+
+            ngx_memcpy(p, ip, len);
+
             sin->sin_addr.s_addr = addr;
 
             r->connection->addr_text.len = len;
-            r->connection->addr_text.data = ip;
+            r->connection->addr_text.data = p;
 
             return NGX_DECLINED;
         }