fastah
// INDIA INTERNET ENGINEERING SOCIETY
IP-based geolocation
The state of the craft, best practices, and the road ahead
Siddharth Mathur
IP data connoisseur · Fastah Inc.
07/2026
// WHY IT EXISTS
Why we geolocate IP addresses
Relevant content
Language, currency and "near me" results that match where the user (roughly) is.
Routing & CDNs
A hint for server selection so traffic lands on a nearby edge.
Streaming rights are territorial. Fencing traffic is key to expensive business models & contractual adherence.
Licensing & geo-blocking
Fraud & security
"Impossible travel" and sanctioned-region flags as one input to risk scoring in financial transactions.
The recurring theme
For some uses a wrong answer is an annoyance; for others it breaks compliance. Same IP geolocation data, but stakes can vary a lot!
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fastah
IIESoc · IP geolocation
Gambling jurisdictions, tax rates, age rules, legal warrant service — location decides which law applies.
Regulation
// THE AWKWARD QUESTION
What an IP "location" actually means
IP addresses were never designed to carry a location. So a single mapping can mean four different things —
and publishers, IP data providers, developers, and consumers often each assume a different one.
INTERPRETATION 1
The user's location
INTERPRETATION 2
The network egress
INTERPRETATION 3
Where the infrastructure sits
INTERPRETATION 4
The regulatory jurisdiction
IIESoc · IP geolocation
fastah
01 / 03
The state of the craft: self-published geofeeds
Instead of trusting a black-box provider, operators can publish the truth about their own address space. Two RFCs make that a standard.
// RFC 8805 · THE FORMAT
RFC 8805 — the geofeed format
A geofeed is just a CSV. One row per prefix:
prefix, country, region, city
geofeed.csv
# prefix, ISO-country, ISO-region, city
150.228.128.0/24, IN, IN-MH, Mumbai
179.65.9.0/24, IN, IN-TN, Chennai
2406:2d40:cc00::/38, IN, IN-DL,
150.228.170.0/24, SG, ,
153.66.76.0/24, , ,
IIESoc · IP geolocation
fastah
// RFC 9632 · FINDING & TRUSTING
RFC 9632 + RFC 9877 — finding and trusting a feed
The format says what a feed contains. RFC 9632 says how the world finds it and believes it. RFC 9877 additionally, helps with finding via RDAP data.
AUTHENTICATE
Attest with RPKI
Cryptographically sign the feed using the same RPKI trust chain that already secures route origin — so nobody can spoof your locations.
CONSUME
One well-known place
Instead of scattered private deals with each data vendor, there is a single canonical source the whole ecosystem can read.
IIESoc · IP geolocation
fastah
DISCOVER
Advertise it in the registry
Add a Geofeed <url> line to your inetnum record at the RIR. Aggregators crawl it automatically.
DISCOVER
Advertise it in the RIR
02 / 03
Best practices for publishers
Publishing a feed is easy. Publishing a good one is about cadence, honesty about precision, and hosting it so crawlers can actually reach it.
// BEST PRACTICE · CADENCE
Set a publishing cadence
Match the refresh rate to how fast your IP ranged are moved around geographically
OPERATOR TYPE
REFRESH
WHY
Small ISP
Monthly
Stable allocations, slow change
Large ISP & mobile carrier
Weekly
Subscriber pools shift more often
Cloud, large CDN, LEO satellite
Daily
Capacity and footprints move constantly
IIESoc · IP geolocation
fastah
// BEST PRACTICE · PRECISION
Think in regions, not points
IP geolocation is statistical and inexact. Plan around a geographic area — never a single pin on a map.
203.0.113.0/24, IN, IN-MH, # anywhere in the state
IIESoc · IP geolocation
fastah
// BEST PRACTICE · GRANULARITY
Vary accuracy on purpose
More precision isn't more helpful. Match the granularity to the network -
coarse for infrastructure, finer for fixed consumers, and never a postal code.
FIXED ISP
City is fine
…, IN-MH, Pune
MOBILE OPERATOR
State only
…, IN-MH,
SATELLITE ISP
Region or country
…, IN, ,
CLOUD / CDN
City of the PoP
…, IN-DL, Delhi
IIESoc · IP geolocation
fastah
// BEST PRACTICE · PUBLISHING
Publish to your RIR, and host with care
One line in your RIR record gives a feed instant, free visibility
inetnum record
remarks: Geofeed https://geo.example.in/rfc8805_feed.csv
HTTPS with always-valid certs
Content-Type: text/csv; charset=utf-8
Welcome crawlers and bots
Don't geo-block your own geofeed
IIESoc · IP geolocation
fastah
// FOR INDIAN OPERATORS
Publish through APNIC
India sits in the APNIC region, so link your Geofeed URL with all your inetnums.
STEP 1
Export from IPAM
Pull your prefixes from IPAM, a database or even a spreadsheet.
STEP 2
Author & validate
Write the RFC 8805 CSV and check every ISO code before you ship.
STEP 3
Host on HTTPS
Put the CSV on a public, always-reachable HTTPS URL.
STEP 4
Tag in APNIC RDAP/Whois
Add the Geofeed line to your APNIC inetnum — and you're live.
IIESoc · IP geolocation
fastah
03 / 03
The road ahead
The IAB gathered the whole ecosystem in December 2025. The verdict: geolocation isn't going away — but the mechanism can and should evolve.
// IAB WORKSHOP · THE GAPS
Room for improvement in the geofeeds ecosystem
FRESHNESS
No TTL, no timestamp
Feeds go stale silently. Blocks sold on the IPv4 market can stay "located" in the wrong country for months.
HARD CASES
CGNAT (a lot in India!) & satellite internet
You geolocate the gateway, not the user. Country accuracy is high (>95%); but city-level is poor.
FALSE SPECIFICITY
Digital sinkholes
Defaulting to a country's centroid or a country’s capital dumps millions of IPs in an indistinguishable locus.
DISCOVERABILITY & TRUST
Need an expanded role for RIRs
RIRs are the natural trust anchors of IP ownership and hence of IP metadata.
IIESoc · IP geolocation
fastah
EXPRESSIVENESS
One address, one place
A CSV row can't say "many locations" or attach a confidence level — so real ambiguity stays hidden.
EXPRESSIVENESS
One address, one place
City and region names vary by typo, language and geopolitics across different feeds. Non-English locales and languages (e.g East Asian nations).
AUTHORING QUALITY AND CONSISTENCY
Geocoding of place names
// IAB WORKSHOP · DIRECTIONS
What the IETF is discussing next
TRACK 1 · EVOLVE THE FEED
A richer, extensible format
A JSON-based feed under discussion, beyond flat CSV
Confidence levels & infra-vs-user tags
Timestamps / TTL and wider RPKI use
TRACK 2 · NEW ARCHITECTURES
Consent-based signals (more GPS oriented; even if fuzzed)
Location as an HTTP client hint
Trusted verifiers & a "geo-CA"
Preferred by smartphones ecosystems owners - Apple and Google
IIESoc · IP geolocation
fastah
// THE WRAP
Three things to take home
01
Own your geo-reputation
A self-published feed beats a vendor guessing at your address space.
02
Coarse location == honest location
When in doubt, prefer state/region geo-resolution over city-level resolution.
03
The format is evolving
CSV works today; a richer, consent-aware future is being written now.
IIESoc · IP geolocation
fastah
fastah
Thank you.
Siddharth Mathur
sid@getfastah.com · Fastah Inc.
India Internet Engineering Society