Virtual Recipients

Virtual Recipients

Admin path: Email Relay > Virtual Recipients (view_virtual_recipients.cfm, inc/addvirtualrecipients.cfm, inc/editvirtualrecipient.cfm, inc/delete_virtual_recipients.cfm).

This page manages forward-only address aliases on the relay-topology domains configured under Domains. Each row in the virtual_recipients table maps one inbound address (or a domain-wide catch-all) to one delivery address, and an address that delivers to several destinations simply has several rows. The delivery target can be internal to Hermes, on another relay domain, on a mailbox domain, or anywhere on the public Internet. The rows are consumed by Postfix's virtual_alias_maps, which concatenates every row it gets back into a single recipient list, so one inbound message fans out to all of them and the forward stays transparent to the original sender.

Virtual recipients have no SMTP authentication, no IMAP/POP3 access, and no password. They are not user accounts. They are rewrite rules.

Not the same as Mailbox Aliases

The Email Server topology has its own alias page — Email Server > Aliases, backed by the mailbox_aliases table — and it serves a different need. The add handler enforces the separation explicitly: trying to add a virtual recipient for a domain flagged as mailbox is rejected with the "use Email Server > Aliases" hint.

The shared mysql-virtual.cf lookup is a UNION across both tables:

SELECT maps          FROM virtual_recipients WHERE virtual_address = '%s'
UNION
SELECT delivers_to   FROM mailbox_aliases    WHERE alias_address   = '%s'

Postfix doesn't care which table the answer comes from — but the admin UI separates them so the rule for each topology stays focused.

Storage and lookup path

The order of these steps matters, and it is not the obvious one. The rewrite is deferred until after content filtering, because main.cf sets receive_override_options = no_address_mappings globally, which disables virtual alias expansion in the cleanup that runs for mail arriving on port 25. The map is still consulted at smtpd to decide whether the recipient exists, but the envelope keeps the original address through the filter.

inbound SMTP (port 25) ──► hermes_postfix_dkim
                                  │
                                  │  smtpd checks: helo, sender, recipient
                                  │  recipient VALIDATED against
                                  │  relay_recipient_maps / virtual_alias_maps
                                  │       ◄── mysql:/etc/postfix/mysql-virtual.cf
                                  │            │
                                  │            ▼
                                  │  ┌────────────────────────────────────┐
                                  │  │ hermes_db_server                   │
                                  │  │  SELECT maps FROM virtual_recipients│
                                  │  │   UNION                            │
                                  │  │  SELECT delivers_to FROM           │
                                  │  │   mailbox_aliases                  │
                                  │  └────────────────────────────────────┘
                                  │
                                  │  cleanup runs with no_address_mappings,
                                  │  so the recipient is NOT rewritten yet
                                  ▼
              content filter (amavis on 10021)
              policy keyed on the ORIGINAL virtual address
                                  │
                                  ▼
                         hermes_ciphermail
                                  │
                                  ▼
              reinjection on :10026, which overrides
              receive_override_options and therefore DOES
              expand virtual_alias_maps
                                  │
                                  ▼
                          rewritten recipient(s)
                                  │
                                  ▼
                       outbound or local delivery

No file regeneration is required when virtual recipients change. The MySQL lookup is live — adding a row in the admin UI takes effect on the next inbound message, with zero Postfix restart or postmap step. This is the operational reason virtual aliases are stored in MySQL rather than a hash file.

The virtual_recipients table

There is no UNIQUE constraint on virtual_address, because a single inbound address fans out to several destinations by holding one row each.

There is deliberately no unique key on the (virtual_address, maps) pair either, even though mailbox_aliases gained one in v260815. Existing installs may already hold exact duplicates, and ADD UNIQUE would abort the whole schema upgrade on the first one it met. The console is the guard instead: Add refuses an address that already exists, so a duplicate pair cannot be created through the UI.

Two address shapes — specific and catch-all

Specific aliases

A regular forward of one address to one destination:

info@company.com       →   owner@company.com
sales@company.com      →   sales-team@externalcrm.example
legal@company.com      →   external-counsel@lawfirm.example

The local-part is rewritten by Postfix after content filtering, at the :10026 reinjection listener. The recipient never sees the original info@/sales@/legal@ address unless the destination mail system surfaces the original envelope.

Catch-alls

A single row starting with @ matches every local-part on the domain that is not already a more specific virtual recipient or a mailbox:

@company.com           →   admin@company.com

With the catch-all row above, mail to jdoe@company.com, random-string@company.com, and does-not-exist@company.com all forward to admin@company.com. Specific aliases on the same domain (info@company.com → owner@company.com) win over the catch-all because they match the more specific lookup key first.

Catch-alls are useful for sunset domains, migration phases, or small domains where one mailbox owner is willing to receive everything. They are not appropriate for high-volume domains: every spam attempt against a random local-part lands in the catch-all destination.

Catch-all visibility in the user portal

A user whose mailbox is the destination of a catch-all (e.g., admin@company.com above) has a special branch in the user portal's Quarantined Messages, Total Messages, and Message History queries. config/hermes/var/www/html/users/2/index.cfm, view_message.cfm, and view_message_history.cfm all consult virtual_recipients for catch-all entries that explicitly map TO the logged-in user, then widen the query with a LIKE '%@domain.tld' clause so the user sees the messages that were swept up by the catch-all. Specific aliases do not get this treatment yet — a known parity gap for the rare case where one user owns many specific aliases and wants the same widened visibility.

Fields on the page

Add Virtual Recipient modal

Opened by the Add Virtual Recipient button above the table. One address per submission, matching Email Server > Aliases.

Because a submission carries exactly one address, it produces exactly one verdict, reported as a single message rather than a tally:

Until v260815 this was a newline-delimited textarea creating many addresses at once. That shape forced every outcome to be an accumulating per-row tally across four separate callouts, and it meant an address that already existed could only be reported rather than refused, because other rows in the same batch still had to process. The trade for the simpler model is that creating several addresses now takes several submissions.

Virtual Recipients table

Standard DataTables surface: searchable, sortable, exportable (copy / CSV / Excel / PDF / print), stateSave: true so column order and page size persist across reloads. Rows are grouped by address, so an entry with twenty destinations is one row with twenty chips.

Actions sits on the left to match Aliases. Note for anyone changing this table: order and columnDefs are index-based and stateSave persists the sort by index, so inserting or removing a column requires updating both plus the stateLoadParams guard.

Edit modal

Edits the whole entry, keyed on the address rather than a row id. The destination set opens as removable chips and the save is a diff: insert what is new, delete what was taken off, leave the rest untouched. Diffing rather than delete-then-reinsert means there is never a moment when the address has no destinations. Re-runs the same domain validation and catch-all detection as Add, including the rejection of mailbox-domain rows.

Adding and removing destinations happens here and only here. Add creates.

Delete

One Delete button per row, confirmed in a modal that names the address and its destination count. The row carries dest_ids, every underlying row id for that address comma-joined by the grouped query, and the handler (delete_virtual_recipients.cfm) runs DELETE FROM virtual_recipients WHERE id = ? per id, so one click removes the address and all of its destinations together. There is no dependency check, because nothing else in the schema points back at a virtual recipient row.

The select-all checkbox column and its bulk Delete Selected button were removed in v260815. They existed because the pre-grouping table rendered one row per destination, so an address with a large destination set filled the screen and needed bulk selection to clear.

Virtual recipients are content filtered

They are filtered exactly like any other inbound mail. This section previously claimed the opposite, and the page carried a callout saying mail through a virtual recipient was delivered "while bypassing ALL content checking (spam, virus, banned files)". Both were wrong. The wording traced back to build-220203 and described no part of this pipeline. Removed in v260815.

Three independent reasons it was never true:

1. content_filter is global. main.cf sets content_filter = amavis:[hermes_mail_filter]:10021 with no per-recipient exception. The only bypass lane in the system is :10030, the BYPASSALLCHECKS policy bank, and it is reachable only through a FILTER action set by Global Sender Block/Allow, which is keyed on the sender.
2. Amavis sees the original address. Because receive_override_options = no_address_mappings defers expansion past the filter, the envelope recipient reaching Amavis is the virtual address itself, not the destination. There is no "post-rewrite recipient" for policy to key on at that point.
3. A domain-scoped policy always matches. Adding a domain inserts an @domain row into recipients carrying the default policy, and Amavis's recipient lookup falls back from user@domain to @domain. The code that does it says so: "ensures Amavis applies SVF filtering to all mail for this domain."

Amavis also classifies the mail correctly as inbound, because @local_domains_maps reads /etc/postfix/relay_domains and the virtual address is on one by definition, since the Add handler refuses any domain that is not configured.

The real caveat with virtual recipients is not filtering, it is forwarding. Mail leaves with the original sender's address, so SPF fails at the receiving end, and if the message was modified on the way through, by an External Banner or LinkGuard, the original DKIM signature no longer validates either. Senders publishing a strict DMARC policy can therefore have mail to external destinations rejected. That warning lives in the Add modal, beside the field it applies to.

Domain-delete dependency

Deleting a relay domain via Domains is blocked when virtual recipients reference it. deletedomain.cfm runs:

SELECT * FROM virtual_recipients WHERE virtual_address LIKE '%<domain>%'

Any match aborts the domain delete with error code 2 and the admin must clear the matching rows from this page before the domain can be removed. The same back-pressure protects against silently stranding a forward when its destination domain disappears.

System-managed rows

A few rows in virtual_recipients are created and managed by the System > Server Setup flow, not by this page directly:

These rows are marked system = '1' (the install/system flow) versus admin-created rows which are marked system = '2'. Editing or deleting a system-managed row from this page works mechanically, but the row will be recreated on the next Server Setup save. Edit the admin email there if you want a different destination for these reserved local-parts; do not maintain them by hand here.

Failure semantics

Bulk import

There is no bulk path. Add creates one address per submission.

Until v260815 the Add card was a newline-delimited textarea and pasting many addresses at once was the practical bulk route. It was removed because a submission carrying many addresses can only report a per-row tally, which is what forced the page's four accumulating callouts and made it impossible to simply refuse an address that already existed. Fan-out in the other direction, one address to many destinations, is unaffected and is entered as chips.

If a bulk path is wanted again it should be a real import with its own report, not a shared text field whose failure mode is a tally.

Files and containers touched

Nothing on this page shells out to Postfix — there is no postmap, no postfix reload, no template regeneration. The MySQL lookup is the only integration surface.

Related

• Domains — the relay-topology domain list these aliases attach to. Domain deletes are blocked when virtual recipients still reference the domain.
• Relay Recipients — recipient validation for domains with Recipient Delivery = SPECIFIED. A specific relay recipient and a virtual recipient can coexist for the same address; the relay recipient wins for recipient-list validation, the virtual recipient still rewrites at delivery.
• Email Server > Aliases — the mailbox- topology equivalent. Aliases for domains where Hermes is the destination MTA live there.
• Email Server > Shared Mailboxes — when several users need to read the same incoming mail (not just one user receiving forwards), use a shared mailbox instead of a fan-out virtual recipient.
• Server Setup — manages the system = '1' postmaster/root/abuse forwards. Change the admin email there to retarget those reserved local-parts.