diff --git a/src/check_fingerprint.py b/src/check_fingerprint.py
index 5d1d3a1..76b7fa1 100644
--- a/src/check_fingerprint.py
+++ b/src/check_fingerprint.py
@@ -3,6 +3,8 @@ import enum
 import entry
 import hashing
 
+# TODO: Include a thing for checking what hosts match a given fingerprint
+
 def check_fingerprint(entries, domain, port, fingerprint):
 	"""check_fingerprint([Entry], str, u16, bytes[32]) → ([str]: successes, [str]: fails)
 	Checks if the given host is found with the given fingerprint.
diff --git a/src/main-export-known-hosts.py b/src/main-export-known-hosts.py
index 7253d73..d02948c 100644
--- a/src/main-export-known-hosts.py
+++ b/src/main-export-known-hosts.py
@@ -6,6 +6,7 @@ import write_file
 def main():
 	# TODO: Don't hardcode
 	# TODO: Handle errors
+	# TODO: Add a switch for whether you want to include IPs
 	with open(sys.argv[1], 'r') as f:
 		try:
 			entries = process_known_hosts.process_file(f)
diff --git a/src/process_known_hosts.py b/src/process_known_hosts.py
index e9c9687..0472900 100644
--- a/src/process_known_hosts.py
+++ b/src/process_known_hosts.py
@@ -25,11 +25,38 @@ class HashedHostError(Exception):
 		else:
 			return 'Line %i: %s' % (self.line, self.string)
 
-def process_line(line):
+def is_ip(domain):
+	"""is_ip(str) → bool
+	Sees if a given domain would be a valid v4 or v6 IP"""
+	def is_ipv4(domain):
+		# IPv4 address has 4 fields separated by .
+		fields = domain.split('.')
+		if len(fields) != 4: return False
+
+		# The fields are base-10 integers
+		fields_num = []
+		for field in fields:
+			try:
+				fields_num.append(int(field, 10))
+			except ValueError:
+				return False
+
+		# The fields are in the range 0…255
+		return all(0 <= field <= 266 for field in fields_num)
+
+	def is_ipv6(domain):
+		# TODO: Implement this
+		return False # FIXME: This is wrong
+
+	return is_ipv4(domain) or is_ipv6(domain)
+
+def process_line(line, ignore_ips):
 	# TODO: Add a way to skip IPs
-	"""process_line(str) → [Entry]
+	"""process_line(str, bool) → [Entry]
 	Given a string containing one line of .ssh/known_hosts file, create
-	a list of Entries based on it."""
+	a list of Entries based on it.
+
+	If ignore_ips is True, only create entries for domain names."""
 	assert type(line) == str
 
 	# Remove trailing newlines
@@ -89,21 +116,28 @@ def process_line(line):
 			domain = host
 			port = 22
 
+		# As we have now extracted the domain, we can check if we
+		# need to throw it out
+		if ignore_ips and is_ip(domain):
+			continue
+
 		# Default to no comment
 		entries.append(entry.create_entry(domain, port, fingerprint, ''))
 
 	return entries
 
-def process_file(f):
-	"""process_file(file(r)) → [Entry]
+def process_file(f, ignore_ips = True):
+	"""process_file(file(r), bool) → [Entry]
 	Given a file in the .ssh/known_hosts format, create a list of
-	entries"""
+	entries.
+
+	If ignore_ips is True, only create entries for domain names."""
 
 	entries = []
 	# Line numbers are 1-indexed but enumerate 0-indexes
 	for linenum_minus_one, line in enumerate(f):
 		try:
-			entries.extend(process_line(line))
+			entries.extend(process_line(line, ignore_ips))
 		except (KnownHostsSyntaxError, HashedHostError) as err:
 			err.line = linenum_minus_one + 1
 			raise err