diff --git a/preprocessing/README.md b/preprocessing/README.md
index f7c3851..bfd5208 100644
--- a/preprocessing/README.md
+++ b/preprocessing/README.md
@@ -1,5 +1,7 @@
 # Data filtering, preprocessing and selection for further use
 
+## Traffic data
+
 - IP packet traces are taken [from here](https://mawi.wide.ad.jp/mawi/samplepoint-F/2023/)
 - Filtering
   - L4 - Limit to TCP and UDP
@@ -15,6 +17,11 @@
   - Packet size - in bytes
 - `sample_output.csv` contains a partial subset of `202310081400.pcap`, ~600K packets
 
+## IP geolocation database
+
+- This project uses the IP2Location LITE database for [IP geolocation](https://lite.ip2location.com)
+- bit of preprocessing to leave out country code and convert IP address from decimal format to dotted string format
+
 # Setting up Kafka
 - Download and install kafka [from here](https://kafka.apache.org/downloads)
 - Run all commands in separate terminals from installation location
diff --git a/preprocessing/ip2loc_prep.py b/preprocessing/ip2loc_prep.py
new file mode 100644
index 0000000..1f604e5
--- /dev/null
+++ b/preprocessing/ip2loc_prep.py
@@ -0,0 +1,49 @@
+import struct
+import socket
+import csv
+
+sample_size = 100
+batch_size = 10000
+
+sample = True
+
+
+def int_to_ipv4(num: int) -> str:
+    return socket.inet_ntoa(struct.pack("!L", num))
+
+
+with open("IP2LOCATION-LITE-DB3.csv", "r") as input_file, open(
+    "geoip.csv", "w", newline=""
+) as output_file:
+    reader = csv.reader(input_file)
+    writer = csv.writer(output_file)
+
+    # header row
+    writer.writerow(
+        [
+            "ip_from",
+            "ip_to",
+            "country",
+            "region",
+            "city",
+        ]
+    )
+
+    records = []
+    for idx, record in enumerate(reader):
+        new_record = [
+            int_to_ipv4(int(record[0])),
+            int_to_ipv4(int(record[1])),
+            record[3],
+            record[4],
+            record[5],
+        ]
+        records.append(new_record)
+        if sample and idx > sample_size:
+            break
+        if idx > 0 and idx % batch_size == 0:
+            writer.writerows(records)
+            records = []
+
+    if len(records) > 0:
+        writer.writerows(records)