Frontier Communications IP Ranges
Frontier Communications runs fibre and copper access networks across a patchwork of US states, announcing them under AS5650. Its largest blocks are the ones that came with Verizon's wireline territory in 2016, and the registry still says Verizon on them.
- Provider
- Frontier Communications
- Primary ASN
- AS5650
- Category
- ISP
- Headquarters
- Norwalk, CT, USA
- Announced IPv4 prefixes
- 1021
- Registry
- ARIN
Known IP ranges
These prefixes are currently announced to the global routing table by AS5650 (FRONTIER-FRTR - Frontier Communications of America, Inc.). Prefix sets change over time - use WHOIS Lookup for the authoritative record on any specific address.
74.32.0.0/12
47.144.0.0/12
47.160.0.0/12
47.192.0.0/12
184.8.0.0/13
47.136.0.0/13
172.76.0.0/14
47.176.0.0/14
184.16.0.0/14
173.84.0.0/14
2a07:a900::/29
2a07:4584::/30
2606:4d80::/32 (IPv6)
What does a Frontier Communications IP mean in a privacy test?
A Frontier address as your visible IP means traffic left over the subscriber line with nothing tunnelling it. If a WHOIS lookup on that address answers Verizon rather than Frontier, that is not an error: a large part of Frontier's space is still registered to the company it bought the territory from, and the reverse DNS is what names the operator actually carrying it.
Where to get Frontier's address list, and why WHOIS may say Verizon
Frontier publishes no range file, so the registry and the routing table are the sources. The prefixes above are the largest currently announced under AS5650, and the AS5650 page carries the registry record beside them.
The per-block records are where this network gets interesting. Frontier completed its purchase of Verizon's wireline operations in California, Texas and Florida on 1 April 2016, and much of the address space came with it without changing hands in ARIN. Look up 47.144.0.0 today and the record is FCC-212, registered to Verizon Business, covering 47.136.0.0/13, 47.144.0.0/12, 47.160.0.0/12, 47.176.0.0/14 and 47.180.0.0/15, allocated on 28 August 2015. Those are blocks Frontier announces. A rule built by matching the WHOIS organisation name puts them on the wrong side of the line.
Reading a Frontier address when the registry disagrees
The reverse DNS is the tie-breaker, and it is unusually descriptive. 47.144.0.1 answers as 47-144-0-1.lsan.ca.frontiernet.net and 74.32.0.1 as 74-32-0-1.dr03.mdtw.ny.frontiernet.net: the address in dashes, then in the second case an equipment identifier, then a location code, then the state, then the frontiernet.net zone. The PTR names Frontier and places the line even where the registry record still names Verizon.
What the combination establishes is a subscriber connection, not a hosted machine: AS5650 is access network, with no rented compute on it for somebody else to run a proxy from, and the location codes describe the serving facility rather than a household. The mismatch is worth remembering in the other direction too. An address that WHOIS attributes to Verizon is not necessarily on Verizon's network today, and the ASN announcing it is the better answer to who is carrying the traffic.
Related tools
Frequently asked questions
What IP ranges does Frontier use?
Frontier announces its address space under AS5650. The largest blocks currently routed there are listed above and include 74.32.0.0/12 along with several blocks inside 47.0.0.0/8. No allowlist is published, so the routing table and the ARIN records for the individual blocks are the sources.
Why does a Frontier IP appear in my privacy test?
A Frontier address as your visible IP means traffic left over the subscriber line with nothing tunnelling it. If a WHOIS lookup on that address answers Verizon rather than Frontier, that is not an error: a large part of Frontier's space is still registered to the company it bought the territory from, and the reverse DNS is what names the operator actually carrying it.
Why does a Frontier IP show as Verizon in WHOIS?
Because the registry record did not move with the territory. Frontier completed its acquisition of Verizon's wireline operations in California, Texas and Florida on 1 April 2016, and the ARIN record covering 47.144.0.0/12 and the blocks around it is still FCC-212, registered to Verizon Business. Frontier announces them, and the reverse DNS names Frontier.
What does a frontiernet.net hostname tell you?
More than most PTR records do. 47.144.0.1 answers as 47-144-0-1.lsan.ca.frontiernet.net, which repeats the address and then gives a location code and a state; some names add an equipment identifier too, as in 74-32-0-1.dr03.mdtw.ny.frontiernet.net. It describes the serving facility, not the customer.
Is a Frontier address a residential line?
Usually. AS5650 carries subscriber access - fibre and copper lines to homes and businesses - rather than rented servers, so an address here is a connection rather than a machine somebody leased. Nothing in the registry labels which lines are residential, so the reverse DNS and the behaviour are what distinguish them.