diff --git a/README.md b/README.md
index 1984ff52..bf5d3751 100644
--- a/README.md
+++ b/README.md
@@ -292,7 +292,7 @@ libgdbm-dev libarchive-zip-perl unzip
 
 sudo perl -MCPAN -e shell
 install Parse::RecDescent XML::LibXSLT DB_File Data::Compare File::Which \
- Marpa::R2 Test::LeakTrace
+ Marpa::R2 Test::LeakTrace IO::Socket::IP
 quit
 ```