Autonomous system
AS11377 SENDGRID
Hosting ARIN
Summary
Twilio SendGrid
hosting enterprise legacy
SENDGRID is SendGrid, Inc. — now Twilio SendGrid — the transactional and marketing email delivery platform. This AS is one of the larger outbound-mail networks on the internet: it exists to originate email on behalf of tens of thousands of customer applications.
What it's used for
RIS sees 130 IPv4 prefixes carrying 263,680 addresses, no IPv6, and 22 observed BGP neighbours. That combination is diagnostic. A quarter of a million addresses behind only twenty-odd peers is not a transit carrier (which would peer with hundreds to thousands) and not an eyeball network; it is a platform that needs address space rather than reach. Email deliverability is scored per sending IP, so an ESP buys and announces large aggregates — 168.245.0.0/18, 159.183.64.0/18, 167.89.0.0/18, several /19s of 149.72.0.0/16 — purely to hand dedicated sending addresses to customers and to keep reputations isolated from one another.
Notable
The reverse DNS shows exactly that model at work. Shared sending addresses resolve to *.outbound-mail.sendgrid.net, while dedicated-IP customers wear their own names on SendGrid space — the sample includes o58.imod2.syr.edu, o2.mails.veracash.com, o1.sgmta.cw.com.tw and o5217.e.ops.jora.com. Customer-branded PTRs on the provider's own prefixes are a deliberate deliverability feature, not a sign the space has been leased away.
Interesting
The prefix registrants split between org SendGrid, Inc. and org Twilio SendGrid (TWILI-11) — a visible fossil of the 2019 Twilio acquisition, and precisely the intra-group registrant pattern that should not be mistaken for third-party address brokerage.
This description is AI-generated, best-effort context — not authoritative, and provided without any guarantee of accuracy. Source, and how to suggest an edit.
Interconnection
Peering at a glance
Internet exchanges
Recorded at 2 exchanges in 1 country, largest first.
| Exchange | Location | Their address |
|---|---|---|
| Equinix Internet Exchange Ashburn | Ashburn, United States | 206.126.237.61 |
| Equinix Internet Exchange Chicago | Chicago, United States | 208.115.136.174 |
Transit providers
10 upstream, 0 downstream and 10 adjacent networks observed; most-used upstreams first.
Exchange presence is recorded rather than inferred: the directory collected by Packet Clearing House (https://www.pch.net/ixp/data) on 2026-10-14, licensed CC BY-NC-SA 3.0. Transit is inferred from observed BGP paths, never declared by either party.
Address space
Summary
IPv4 41 prefixes · 264K addresses IPv6 0 prefixes
| Country | Name | Prefixes |
|---|---|---|
| US | United States of America | 41 |
Registry
Allocation record
- Registry
- ARIN
- Handle
AS11377- Registry name
- SENDGRID
- Registrant
- SendGrid, Inc.
- Abuse contact
- abuse@sendgrid.com
- Registered
- 2012-06-28
- Last changed
- 2012-06-28
- Allocation
- assigned
Routing security
RPKI and IRR
- RPKI
- 100% valid · 139 valid, 0 with no ROA
- ROAs
- 150 authorising AS11377
- ASPA
- no ASPA record
- IRR
- 100% registered · 139 of 139 announcements
- Route objects
- 327 naming AS11377
Reputation
Classification and threat
Hosting Datacenter or cloud provider. Addresses are servers, not people.
Spamhaus DROP
Not on ASN-DROP The network as a whole is not listed.
No DROP prefixes None of its announced space is on the DROP prefix list.
Spamhaus DROP ("Don't Route Or Peer") lists space and networks run by, or hijacked for, spam and cybercrime operations: 442 networks and 1,773 prefixes, as published 2026-10-13. A short, high-confidence list, so a match is worth taking seriously, and absence from it says little on its own.
FBI IC3
No IC3 indicators Nothing from the FBI IC3 feed.
IC3 threat data is alpha. Absence of an indicator is not evidence of good behaviour, only of absence from this one feed.
Elsewhere