diff --git a/examples/webbrowser/Makefile.atari.defines b/examples/webbrowser/Makefile.atari.defines
index 7713f7f1e..54380b38d 100644
--- a/examples/webbrowser/Makefile.atari.defines
+++ b/examples/webbrowser/Makefile.atari.defines
@@ -1 +1 @@
-DEFINES = WITH_CLIENT,WITH_DNS,WITH_GUI,MTU_SIZE=900
+DEFINES = WITH_CLIENT,WITH_DNS,WITH_GUI,MTU_SIZE=1000