diff --git a/src/operators/rbl.cc b/src/operators/rbl.cc
index 894f9dc8..9190407b 100644
--- a/src/operators/rbl.cc
+++ b/src/operators/rbl.cc
@@ -228,7 +228,7 @@ bool Rbl::evaluate(Transaction *t, RuleWithActions *rule,
 
     // SonarCloud suggested to use the init-statement to declare "addr" inside the if statement.
     // I think that's not good here, because we need that in the else block
-    struct sockaddr *addr = info->ai_addr;  // NOSONAR
+    const struct sockaddr *addr = info->ai_addr;  // NOSONAR
     if (addr->sa_family == AF_INET) {  // NOSONAR
         struct sockaddr_in sin{};  // initialize an empty struct; we don't need port info
         memcpy(&sin.sin_addr, addr->sa_data + 2, sizeof(sin.sin_addr));