Optus IP Ranges
Optus is the Australian carrier owned by Singtel, and AS4804 is the access network its retail broadband and mobile customers sit behind. The APNIC record does not say Optus anywhere obvious - the ASN is named MPX-AS and described as Microplex PTY LTD and Australia Border AS. It is Optus all the same: the organisation handle on it, ORG-SOPL2-AP, is the one that also holds AS7474 for SingTel Optus Pty Ltd of 101 Miller St, North Sydney, the incident-response team on it is IRT-OPTUSCOM-AU, and the PeeringDB entry for AS4804 is filed as Optus Internet, also known as OptusNet. How the number passed from Microplex to Optus is not recorded in the registry.
- Provider
- Optus
- Primary ASN
- AS4804
- Category
- ISP
- Headquarters
- Sydney, Australia
- Announced IPv4 prefixes
- 281
- Registry
- APNIC
Known IP ranges
These prefixes are currently announced to the global routing table by AS4804 (MPX-AS - Microplex PTY LTD). Prefix sets change over time - use WHOIS Lookup for the authoritative record on any specific address.
49.176.0.0/12
175.32.0.0/13
58.104.0.0/13
122.104.0.0/13
49.192.0.0/13
114.72.0.0/14
220.236.0.0/14
211.28.0.0/14
1.40.0.0/14
110.20.0.0/14
2405:dc00:8000::/33
2405:dc00:ff::/48
2405:dc00:ec93::/48 (IPv6)
What does an Optus IP mean in a privacy test?
The reverse name on an Optus fixed line is more informative than most geolocation lookups, because Optus writes the state into it. 49.192.200.100 answers as n49-192-200-100.per2.wa.optusnet.com.au - an n prefix and the dashed address, then a facility code, then wa for Western Australia; 175.32.200.100 comes back mas22.nsw for New South Wales, 58.104.100.50 as mrk2.qld and 122.104.100.100 as sun4.vic. A fixed assignment is flagged by a static- prefix in front of the whole name, as in static-n49-176-200-100.rdl2.qld.optusnet.com.au. Other addresses publish no reverse name at all even though Optus runs the zone, and there the registry is what you have left: 211.28.0.0/14 is described in APNIC as OPTUS INTERNET - RETAIL out of Chatswood, Sydney.
Three different Optus names across the records
The address space and the ASN are registered to different Optus entities, which is the single most confusing thing about looking this network up. The blocks belong to Optus Internet Pty Ltd under ORG-OIPL5-AP, with the netname OPTUSINTERNET-AU and the abuse team IRT-OPTUSINTERNET-AU - that covers 49.176.0.0/12, described at 1 Lyonpark Road, and 211.28.0.0/14, described OPTUS INTERNET - RETAIL at Chatswood, Sydney, both status ALLOCATED PORTABLE and neither carrying a geofeed. The ASN sits under a different object, ORG-SOPL2-AP, SingTel Optus Pty Ltd of 101 Miller St, North Sydney.
What Optus publishes sits on the AS7474 side rather than this one. There is a public looking glass at looking-glass.optus.net.au, and the AS7474 PeeringDB record documents a BGP community scheme that tags customer routes by Australian state: 7474:1201 for ACT, 7474:1202 NSW, 7474:1203 VIC, 7474:1204 QLD, 7474:1205 SA, 7474:1206 WA, 7474:1207 TAS and 7474:1208 NT, with 7474:1402 marking Asian routes and 7474:1403 US routes, alongside local-preference communities 7474:100, 7474:90, 7474:80 and 7474:70. The AS-SET is on that side too: AS7474 gives PeeringDB APNIC::AS7474:AS-OPTUS, while the AS4804 record lists no IRR AS-SET of its own.
Retail line, business line, or no name at all
The routing policy on the aut-num settles the first question. AS4804 imports only from AS7474, with from AS7474 action pref=100; accept ANY, and exports only to AS7474 announce AS4804, so it is a stub sitting behind Optus's other ASN rather than a network with transit of its own. Optus spells the division out in its own PeeringDB notes: AS4804 is the mobile, DSL and cable ISP, while AS7474 is the business and wholesale ISP with the direct international and domestic peering. An address on AS4804 is a retail service; the same brand seen on AS7474 is far more likely to be a business circuit or a wholesale customer.
After that the hostname does the work, and its absence is not the signal it looks like. Fixed lines carry n plus the dashed address, a facility code, a state and optusnet.com.au, and a fixed assignment prefixes the lot with static-. Addresses sampled in 211.28.0.0/14, 220.236.0.0/14 and 114.72.0.0/14 returned no PTR - but the SOA served for those zones is ns1.syd.optusnet.com.au, so Optus operates the reverse zone and has simply not populated the record. Other large blocks are fully named: 110.20.0.0/14 and 122.104.0.0/13 both resolve normally, into qld and vic respectively. A missing hostname on this network means an unpopulated record, not space outside the optusnet.com.au zone.
Related tools
Frequently asked questions
Why does the registry say Microplex rather than Optus?
Because the ASN record still carries an older holder name. AS4804 is named MPX-AS in APNIC and described as Microplex PTY LTD and Australia Border AS. Everything around it is Optus: the organisation handle ORG-SOPL2-AP is shared with AS7474 for SingTel Optus Pty Ltd, the incident-response team is IRT-OPTUSCOM-AU, and the PeeringDB entry names the network Optus Internet. The registry does not record how or when the number changed hands.
What is the difference between AS4804 and AS7474?
Optus describes it itself in PeeringDB: AS4804 is the mobile, DSL and cable ISP, and AS7474 is the business and wholesale ISP carrying the direct international and domestic peering. The aut-num backs that up, since AS4804 accepts routes only from AS7474 and announces only to it.
What does the state code in an Optus hostname mean?
It is Optus stating which Australian state the line terminates in. A fixed-line reverse name runs n, the dashed address, a facility code, the state and optusnet.com.au, so n175-32-200-100.mas22.nsw.optusnet.com.au is a New South Wales line and n49-192-200-100.per2.wa.optusnet.com.au is a Western Australian one. Optus uses state codes on the routing side too, tagging customer routes with BGP communities 7474:1201 through 7474:1208.
Why do some Optus addresses have no reverse name?
Because the record is missing, not the delegation. Addresses sampled in 211.28.0.0/14, 220.236.0.0/14 and 114.72.0.0/14 returned nothing, yet the SOA for those reverse zones is ns1.syd.optusnet.com.au, so Optus holds the zone either way. Other blocks of the same size, such as 110.20.0.0/14 and 122.104.0.0/13, are named normally. Optus has published no statement on which pools get names.
Does Optus publish a geofeed?
No. Neither of the APNIC objects covering its retail allocations, 49.176.0.0/12 and 211.28.0.0/14, carries a geofeed attribute. The nearest published equivalents are the state codes in the optusnet.com.au reverse names and the state-tagged BGP communities in the AS7474 PeeringDB record, and neither is an RFC 8805 file that geolocation databases can ingest directly.