diff --git a/bpftools/p0f.py b/bpftools/p0f.py
index 3c3169a..5d72f87 100644
--- a/bpftools/p0f.py
+++ b/bpftools/p0f.py
@@ -52,6 +52,8 @@ def parse_ittl(self):
         if self.ittl.endswith("-"):
             self.ttl_rand = True
         else:
+            if "+" in self.ittl:
+                self.ittl, _ = self.ittl.split("+")
             self.ttl_rand = False
 
     def parse_win_size(self):
@@ -78,7 +80,7 @@ def parse_sig(self):
         if self.ver != '4' and self.ver != '6':
             raise ValueError("IP version must be either 4 or 6")
 
-        if not re.match("^(\d+)-?$", self.ittl):
+        if not re.match("^(\d+)(-|\+\d+|\+\?)?$", self.ittl):
             raise ValueError("Invalid ttl field")
         self.parse_ittl()