subnet.im

AS18403FPT Telecom Company

VietnamRegistryAPNICTypeEyeball

As of 26th September 2026, AS18403 (FPT Telecom Company), an access network registered in Vietnam with APNIC, originates 4,734 IPv4 prefixes covering 6.2M addresses and 3,769 IPv6 prefixes. By IPv4 address space that makes it the 118th-largest of the 79,480 networks we see originating IPv4, and the 3rd-largest of 523 in Vietnam. It is seen behind 75 upstream networks, most often AS3356 (Lumen (Level 3)) and AS8220 (COLT), and in front of 255 downstream networks. Over 99% of its announcements have a valid RPKI ROA; 26 are RPKI-invalid. 11% of its routes reach at least 90% of full-feed peers, and 1 prefix is also originated by another network.

At a glance

IPv4 prefixes

4,734

IPv6 prefixes

3,769

IPv4 addresses

6.2M

IPv6 /64s

42.3B

Upstream graph

The networks AS18403 is seen behind, one and two hops out, drawn from real AS paths.

AS18403Toward the internet core
Upstream graph for AS18403: 12 neighbouring networks observed beyond it across 2 levels. The same networks are listed in the tables below.AS18403FPT Telecom Compa…This networkAS1299Arelion (fka. Tel…AS3356Lumen (Level 3)AS4637Telstra Internati…AS6939Hurricane Electri…AS8220COLTAS8888xTom Pty LtdAS13030Init7 (Switzerlan…AS2914NTT America, Inc.AS3549Lumen (fka. Globa…AS18106Viewqwest Pte LtdAS20130Depaul UniversityAS15576NTS workspace AG

Networks observed one and two hops upstream of AS18403 in real AS paths. A thicker line means more vantage points saw that adjacency, so weight tracks how well attested it is — not how much traffic it carries. Adjacency is an observation; whether it is a transit purchase or a settlement-free peering is an inference, and is labelled as one wherever we show it.

Neighbouring networks

1,101

adjacent networks

Upstreams
757%
Peers
77170%
Downstreams
25523%

Networks carrying this one's traffic toward the rest of the internet. Listing the 40 seen on the most AS paths, of 75.

Upstreams of AS18403
NetworkCountryRelationshipPathsVantage pts
AS3356Lumen (Level 3)USPeer27,29495
AS8220COLTGBPeer25,9686
AS1299Arelion (fka. Telia Carrier)SEPeer25,21098
AS6939Hurricane Electric LLCUSPeer22,5035
AS4637Telstra International LimitedHKPeer22,435109
AS35280F5 Networks SARLFRPeer19,6346
AS14537Continent 8 LLCUSPeer19,5884
AS18106Viewqwest Pte LtdSGPeer13,9844
AS4229Zenlayer IncUSPeer12,355112
AS49544i3D.net B.VNLPeer11,9184

Prefixes

All 8,503

The largest blocks AS18403 originates, widest first.

Largest prefixes originated by AS18403
PrefixAddressesVisibility
42.112.0.0/13524k80/81
1.52.0.0/14262k81/81
118.68.0.0/14262k81/81
58.186.0.0/15131k81/81
118.68.0.0/15131k81/81
42.112.0.0/1665.5k81/81
42.113.0.0/1665.5k81/81
42.114.0.0/1665.5k81/81
42.115.0.0/1665.5k81/81
42.116.0.0/1665.5k81/81

Routing health

How AS18403's own announcements validate against RPKI and how far they propagate. The same measures for the whole routing table are on the routing table in numbers.

RPKI origin validation

  • Valid99.7%8,474
  • Invalid0.3%26
  • No ROA<0.1%3

Propagation

  • Globally propagated90% of full-feed peers or more10.9%930
  • Partially propagated40% to 90%1.0%87
  • Seen by few peersUnder 40%88.0%7,486

Prefix sizes

IPv4 — 4,734 prefixes

IPv6 — 3,769 prefixes

  • /3017.2B × /64<0.1%1
  • /324.3B × /640.1%4
  • /36268M × /640.5%20
  • /37134M × /640.1%5
  • /418.4M × /64<0.1%1
  • /432.1M × /641.3%50
  • /441M × /6433.4%1,258
  • /45524k × /640.6%21
  • /46262k × /6419.6%739
  • /47131k × /6443.0%1,621
  • /4865.5k × /640.6%23
  • /49 and longerAggregated0.7%26

Recent changes

Announcements that started or stopped since 27th Aug 2026.

500 announced and 93 withdrawn in all; the most recent are shown.

Routing data derived from RouteViews MRT archives, BGPKIT relationship inference and public registry data.