diff --git a/src/test/net_tests.cpp b/src/test/net_tests.cpp
--- a/src/test/net_tests.cpp
+++ b/src/test/net_tests.cpp
@@ -181,6 +181,8 @@
 
 BOOST_AUTO_TEST_CASE(test_userAgentLength) {
     GlobalConfig config;
+
+    config.SetMaxBlockSize(8000000);
     std::string long_uacomment = "very very very very very very very very very "
                                  "very very very very very very very very very "
                                  "very very very very very very very very very "