Bingbot

Bingbot crawls and renders pages for the Bing index, which also supplies results to Microsoft Copilot. Aiola classifies it as indexing because it supports a searchable retrieval index.

In Aiola's taxonomy, Indexing means crawled for ai or search indexing.

Look for the match token inside the complete HTTP User-Agent header. Tokens can be spoofed, so use the network checks below for authentication.

Mozilla/5.0 (compatible; bingbot/2.0; +http://www.bing.com/bingbot.htm)

Bingbot

Microsoft publishes an official IP range list. This cached snapshot contains 28 CIDR prefixes, last fetched 2026-10-23. Open the live source

13.66.139.0/24
13.66.144.0/24
13.67.10.16/28
13.69.66.240/28
13.71.172.224/28
139.217.52.0/28
157.55.39.0/24
191.233.204.224/28
199.30.24.0/23
20.125.163.80/28
20.15.133.160/27
20.36.108.32/28
20.43.120.16/28
20.74.197.0/28
20.79.107.240/28
207.46.13.0/24
40.77.139.0/25
40.77.167.0/24
40.77.177.0/24
40.77.178.0/23
40.77.188.0/22
40.77.202.0/24
40.79.131.208/28
40.79.186.176/28
51.105.67.0/28
52.167.144.0/24
52.231.148.0/28
65.55.210.0/24

For Bingbot, compare the source IP from your trusted edge or server against Microsoft’s current published prefixes.

python3 -c 'import ipaddress; print(ipaddress.ip_address("REQUEST_IP") in ipaddress.ip_network("13.66.139.0/24"))'

Test every current prefix in the vendor feed and re-fetch it regularly. This cached snapshot is evidence of publication, not a permanent firewall list.

Microsoft documents crawler controls for this bot family. Robots.txt can direct cooperative crawling, but it cannot prove that a request is authentic.

User-agent: bingbot
Allow: /

User-agent: bingbot
Disallow: /

Read official crawler documentation