Egress Defend (UK) email service provider (ESP)
According to Live Direct Marketing's daily Tranco top-1M scan (September 16, 2026), Egress Defend (UK) is the email service provider (ESP) for 171 domains — 0.03% of 634,905 SPF-publishing domains. Detection method: include: mechanisms in the SPF record.
Key facts
- 171 domains in the Tranco top-1M use Egress Defend (UK) (0.03% of SPF-publishing domains).
- Snapshot date: 2026-09-16 — recomputed every day.
- Strongest TLD: .com (90.6% of its domains).
- Most co-used service: Proofpoint.
- Directory category: email security gateway.
Why Egress Defend (UK) appears in this category
UK Egress (KnowBe4 group) inbound defense.
We classify it as a email security gateway from include: mechanisms in the SPF record matching a maintained provider rule. This is infrastructure attribution from public DNS, not evidence of a direct contract or exclusive use.
Egress Defend (UK) is an email security and outbound gateway solution that organisations use to filter, inspect, and control the email messages they send. It operates as an authorised outbound email service, appearing in the SPF records of organisations that route their email through its infrastructure.
Its presence in SPF records across established, higher-traffic websites—predominantly in the .com domain space and frequently seen deployed alongside Proofpoint—reflects adoption by organisations prioritising email security and compliance. For senders and deliverability professionals, this pattern indicates that recipient organisations using Egress Defend have implemented gateway-level email security controls, which may influence message handling, latency, and policy enforcement in ways that matter for sender reputation management and delivery performance.
Where Egress Defend (UK) sits in the Tranco ranking
| Tranco rank band | Domains | Share of its base |
|---|---|---|
| Top 1,000 | 0 | 0.0% |
| Top 10,000 | 2 | 1.2% |
| Top 100,000 | 64 | 37.4% |
| Top 1,000,000 | 104 | 60.8% |
| Unranked | 1 | 0.6% |
Top-level domain split
| TLD | Domains | Share | |
|---|---|---|---|
| .com | 155 | 90.6% | |
| .org | 4 | 2.3% | |
| .tv | 4 | 2.3% | |
| .net | 2 | 1.2% | |
| .com.au | 1 | 0.6% | |
| .ie | 1 | 0.6% | |
| .bank | 1 | 0.6% | |
| .gov | 1 | 0.6% | |
| .ai | 1 | 0.6% | |
| .eu | 1 | 0.6% |
What Egress Defend (UK) users also use
Cross-tabulated from the same daily snapshot — the other email services seen on the same 171 domains.
| Type | Service | Domains | Share of Egress Defend (UK) users |
|---|---|---|---|
| Mailbox | Proofpoint | 133 | 77.8% |
| Mailbox | Microsoft 365 | 33 | 19.3% |
| Mailbox | Self-Hosted | 2 | 1.2% |
| Mailbox | Mimecast | 1 | 0.6% |
| Mailbox | Unknown / Other | 1 | 0.6% |
| ESP | Salesforce | 13 | 7.6% |
| ESP | Mailchimp | 7 | 4.1% |
| ESP | HubSpot | 3 | 1.8% |
| ESP | MailChannels | 2 | 1.2% |
Outbound Email Gateway Architecture and SPF Authentication
Organisations deploying Egress Defend publish its IP ranges in their SPF records to authorise the gateway to send email on their behalf. Mail destined for such organisations passes through this intermediate security layer, where it may be subject to scanning, policy evaluation, or delayed processing before final delivery. Understanding this gateway hop is relevant when investigating slow delivery, temporary rejections, or unusual bounce patterns, as the delay or policy outcome originates at the sending organisation's own infrastructure rather than at the recipient mail server.
See the full Egress Defend (UK) data page (KPI cards, trend, sample domains) →
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Frequently asked questions
What is Egress Defend and why does it appear in SPF records?
Egress Defend is an outbound email security gateway used by organisations to inspect and control their sent email. It appears in SPF records because organisations authorise its servers to send mail on their behalf, the same way any outbound email service is declared in authentication records.
How many domains use Egress Defend (UK)?
171 domains in the Tranco top-1M use Egress Defend (UK) as their email service provider (ESP) as of September 16, 2026 (0.03% of SPF-publishing domains), according to Live Direct Marketing's daily DNS scan.
Is Egress Defend (UK) common enough to affect email deliverability testing?
Egress Defend (UK) accounts for 0.03% of SPF-publishing domains in the top 1M. Whether you should seed a test mailbox there depends on how much of your audience it represents — the co-usage table above shows the services it appears alongside most.
Which countries or TLDs use Egress Defend (UK) most?
Egress Defend (UK)'s largest TLD is .com (90.6% of its domains); it appears across 10 TLDs in total.