diff --git a/src/cfnlint/helpers.py b/src/cfnlint/helpers.py
index 54436ada..e1d29897 100644
--- a/src/cfnlint/helpers.py
+++ b/src/cfnlint/helpers.py
@@ -67,7 +67,7 @@ FN_PREFIX = 'Fn::'
 CONDITION_FUNCTIONS = ['Fn::If']
 REGIONS = list(SPEC_REGIONS.keys())
 
-REGEX_ALPHANUMERIC = re.compile('^[a-zA-Z0-9]*$')
+REGEX_ALPHANUMERIC = re.compile('^[a-zA-Z0-9-.]*$')
 REGEX_CIDR = re.compile(
     r'^(([0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])\.){3}([0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])(\/([0-9]|[1-2][0-9]|3[0-2]))$')
 REGEX_IPV4 = re.compile(