Zayo Group IP Ranges
Zayo Group sells dark fibre, wavelengths and IP transit, but AS6461 is a good deal older than the company. ARIN registered the number on 22 April 1996 and the record now reads ZAYO-6461 to Zayo Bandwidth, while PeeringDB still lists the network as also known as AboveNet and MFNX, names AS-MFNX as its route registry object, and declares 20 to 50 Tbps of traffic. The address blocks carry the older identity too: the ARIN allocation covering 64.125.0.0/16 has been called ABOVENET since 6 July 2000.
- Provider
- Zayo Group
- Primary ASN
- AS6461
- Category
- Transit
- Headquarters
- Boulder, CO, USA
- Announced IPv4 prefixes
- 221
- Registry
- ARIN
Known IP ranges
These prefixes are currently announced to the global routing table by AS6461 (ZAYO-6461 - Zayo Bandwidth). Prefix sets change over time - use WHOIS Lookup for the authoritative record on any specific address.
208.184.0.0/15
216.191.0.0/16
74.216.0.0/16
159.18.0.0/16
209.249.0.0/16
216.13.0.0/16
144.83.0.0/16
64.125.0.0/16
167.217.0.0/16
128.177.0.0/16
2a00:16f8::/32
2001:438::/32
2001:4c8::/32 (IPv6)
What does a Zayo Group IP mean in a privacy test?
An address on AS6461 shown as your exit is a business circuit or a hosted machine, because Zayo sells transit and fibre rather than consumer lines. The registry is unusually helpful here: dedicated internet access blocks are written into ARIN as their own assignment records, under netnames built from a fixed ZAYO-IDIA prefix, an order number and the block, and the registrant on that assignment is the customer rather than Zayo. So a whois lookup on the exact address, rather than on the allocation above it, will often name the actual business behind it. Zayo makes the same split visible in BGP, tagging a route learned from a customer 6461:5998 and one learned from an internal resource 6461:5999. What no record here states is a location, because Zayo files no geolocation feed, so any city a lookup shows you for this space was inferred by a commercial database rather than declared by the operator.
Where Zayo publishes machine-readable data about AS6461
Zayo files no geolocation feed, and none of the ARIN records behind its largest blocks points at one. 64.125.0.0/16 sits inside a direct allocation named ABOVENET that also covers 64.124.190.0/23 and 64.124.192.0/18, registered 6 July 2000; 128.177.0.0/16 is ABOVENET-128-177 from 28 July 1997; 216.191.0.0/16 is ZAYO-CAN-8 from 15 June 1999. Each carries an abuse contact and little else, and it is the same abuse role on all of them and on the aut-num, now marked with an ARIN remark that ARIN tried to validate the contact and has had no response since 18 December 2024. With no operator statement of location to read, the routing table and the assignment record are what you have.
What Zayo does document is the routing. Its community page lists the informational tags a customer sees - 6461:5999 for a route learned from an internal resource, 6461:5998 from a customer, 6461:5997 from a peer, 6461:5995 across a public peering exchange, with 6461:5996 and 6461:5994 narrowing that to EU and APAC sessions - and the controls a customer sends back: 6461:5000 to suppress an announcement to all peers, 6461:5010, 6461:5014 and 6461:5018 for EU, APAC and LATAM peers, and 6461:5990 to blackhole. The IRR object named in its PeeringDB record is AS-MFNX and the looking glass is lg.zayo.com/lg.cgi. The peering policy is not readable on the web at all: the page for it carries one sentence of description and a PDF download, so its thresholds are not something you can quote from the site.
Reading a Zayo address in a log
Zayo's own routers name themselves in reverse DNS, in a scheme that reads right to left: interface, router, site, country, domain. Three lookups taken from public DNS while this page was written. 195.66.224.76 returns ae15.mpr1.lhr15.uk.above.net; 80.249.208.122 returns er1.ams1.nl.above.net; 80.81.194.26 returns decix-ae3.mpr1.fra4.de.zip.zayo.com. Two domains for one network, above.net surviving from the AboveNet estate and zip.zayo.com being the newer one, and a hostname in either is Zayo equipment rather than somebody renting from Zayo.
Everything else on the ASN is a customer machine, and ARIN will usually tell you whose. Zayo writes dedicated internet access blocks into the registry as assignment records nested under its own allocations, with a netname built from a fixed prefix, an order number and the block itself - ZAYO-IDIA-179331-208-184-0-0-24, registered in July 2019 inside 208.184.0.0/15, is one live example - and the registrant on that assignment is the company that bought the circuit, not Zayo. So query the exact address rather than the covering block: the allocation above it answers Zayo Bandwidth every time, while the assignment underneath may name a specific enterprise. Because these are assignments and not a subscriber pool, the block is delegated to that business and behaves that way, inbound connections included, and where the exact address returns no assignment you are looking at Zayo's own equipment or at space it has not sub-delegated.
Related tools
Frequently asked questions
Why does AS6461 still say AboveNet?
Because the number and much of the address space predate Zayo. ARIN registered AS6461 in April 1996, the allocation containing 64.125.0.0/16 still carries the netname ABOVENET from July 2000, and the route registry object Zayo names in PeeringDB is AS-MFNX. Zayo took the network over and kept the registry objects rather than renaming them.
Does Zayo publish a geofeed for its ranges?
No geolocation feed is referenced from any of the ARIN records for its largest blocks. Those records carry an abuse contact and no geolocation URL, so a city shown for a Zayo address comes from a commercial database inferring it rather than from Zayo stating it.
Whose name is on a Zayo address in whois?
It depends which object you query. The covering allocation is registered to Zayo Bandwidth, but Zayo writes customer circuits into ARIN as separate assignment records with netnames of the form ZAYO-IDIA, an order number and the block, and the registrant on those is the business that bought the circuit. Querying the exact address rather than the /16 is what surfaces that name.
Where can I read Zayo's peering policy?
Only as a PDF. The page on zayo.com for its global peering and interconnection policy carries a single sentence saying the policy covers selection of peers for AS6461, plus a download link, and no thresholds or requirements appear in the page text itself.
Is the abuse contact on a Zayo record current?
Treat it with care. The same abuse role covers the aut-num and the large ARIN allocations, and ARIN has appended a remark to it stating that it attempted to validate the contact and has received no response since 18 December 2024. If a customer assignment exists for the exact address, the organisation on that record is a second place to send a report.