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Add reverse lookup and forward confirmation

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nemunaire 2025-10-23 15:59:57 +07:00
commit 84a504d668
8 changed files with 324 additions and 5 deletions
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103
web/src/lib/components/PtrForwardRecordsDisplay.svelte Normal file
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<script lang="ts">
interface Props {
ptrRecords?: string[];
ptrForwardRecords?: string[];
senderIp?: string;
}
let { ptrRecords, ptrForwardRecords, senderIp }: Props = $props();
// Forward-confirmed reverse DNS is valid if:
// 1. PTR records exist
// 2. Forward records exist
// 3. At least one forward record matches the original sender IP
const fcrDnsIsValid = $derived(
ptrRecords &&
ptrRecords.length > 0 &&
ptrForwardRecords &&
ptrForwardRecords.length > 0 &&
senderIp &&
ptrForwardRecords.includes(senderIp),
);
const hasForwardRecords = $derived(ptrForwardRecords && ptrForwardRecords.length > 0);
</script>
{#if ptrRecords && ptrRecords.length > 0}
<div class="card mb-4">
<div class="card-header d-flex justify-content-between align-items-center">
<h5 class="text-muted mb-0">
<i
class="bi"
class:bi-check-circle-fill={fcrDnsIsValid}
class:text-success={fcrDnsIsValid}
class:bi-x-circle-fill={!fcrDnsIsValid}
class:text-danger={!fcrDnsIsValid}
></i>
Forward-Confirmed Reverse DNS
</h5>
<span class="badge bg-secondary">FCrDNS</span>
</div>
<div class="card-body">
<p class="card-text small text-muted mb-0">
Forward-confirmed reverse DNS (FCrDNS) verifies that the PTR hostname resolves back
to the original sender IP. This double-check helps establish sender legitimacy.
</p>
{#if senderIp}
<div class="mt-2">
<strong>Original Sender IP:</strong> <code>{senderIp}</code>
</div>
{/if}
</div>
{#if hasForwardRecords}
<div class="list-group list-group-flush">
<div class="list-group-item">
<div class="mb-2">
<strong>PTR Hostname(s):</strong>
{#each ptrRecords as ptr}
<div class="mt-1">
<code>{ptr}</code>
</div>
{/each}
</div>
<div class="mb-2">
<strong>Forward Resolution (A/AAAA):</strong>
{#each ptrForwardRecords as ip}
<div class="d-flex gap-2 align-items-center mt-1">
{#if senderIp && ip === senderIp}
<span class="badge bg-success">Match</span>
{:else}
<span class="badge bg-warning">Different</span>
{/if}
<code>{ip}</code>
</div>
{/each}
</div>
{#if fcrDnsIsValid}
<div class="alert alert-success mb-0 mt-2">
<i class="bi bi-check-circle me-1"></i>
<strong>Success:</strong> Forward-confirmed reverse DNS is properly configured.
The PTR hostname resolves back to the sender IP.
</div>
{:else}
<div class="alert alert-warning mb-0 mt-2">
<i class="bi bi-exclamation-triangle me-1"></i>
<strong>Warning:</strong> The PTR hostname does not resolve back to the sender
IP. This may impact deliverability.
</div>
{/if}
</div>
</div>
{:else}
<div class="list-group list-group-flush">
<div class="list-group-item">
<div class="alert alert-danger mb-0">
<i class="bi bi-x-circle me-1"></i>
<strong>Error:</strong> PTR hostname(s) found but could not resolve to any IP
addresses. Check your DNS configuration.
</div>
</div>
</div>
{/if}
</div>
{/if}