To migrate many email aliases safely, inventory every local-part and destination before you touch MX. Create the map on MailerZ first. Lower TTL if you still can. Screenshot the old MX. Cut over to one exclusive set. Probe a sample, then the rest. Rollback is republishing the screenshot, not inventing a dual-MX “safety net.” Dual MX is how you lose mail during a hundred-alias move.
Quick answer for migrate many email aliases
A hundred aliases fail as a project when the sheet is incomplete. The MX cut is the easy minute. The map is the week.
RFC 1035 is why TTL and nameservers matter. If you edit the registrar while NS points at Cloudflare, you migrated nothing.
Parallel configuration means MailerZ is fully mapped while old MX still answers. Users feel nothing until you cut.
Agencies should refuse a cutover date until the sheet reconciles with the old host’s export. Missing rows become incident tickets.
HOLD unknown during the move. People will guess local-parts that were never real. FORWARD will hide the misses in junk.
Soft CTA: use the migration planner and start free on a single domain as a dress rehearsal if you have never cut MX before.
Authoritative mail transport is defined in IETF RFC 1035 — Domain names. Product path: migration planner, docs, and troubleshooting.
User problem and decision criteria
Decision criteria: complete inventory, destination validity, TTL headroom, who can edit NS, rollback screenshot, probe owners.
Criteria that do not belong: dual MX, catch-all FORWARD to paper over a bad sheet, inboxing promises, weekend heroics without a sheet.
If the old host cannot export aliases, you will discover them from invoices and websites. Budget that archaeology.
Shared destinations need a human owner in the sheet. “Team@” with no person is how mail sits unseen after a successful hop.
Send-as can wait a day. Inbound aliases are the cutover. Do not combine AUTH debugging with MX day.
Legal names and role addresses are contracts. Migrate those first in the sample.
If two companies share a domain, stop. That is not a hundred-alias move. That is a governance fight.
Free allows three aliases. A hundred aliases is a paid-plan conversation. Quote pricing. Do not invent unlimited.
Technical mail flow
Export old aliases. Normalize local-parts. Create on MailerZ. Verify destinations.
Lower TTL. Wait. Screenshot old MX. Publish exclusive MailerZ MX. Delete leftovers.
Probe sample. Fix misses. Probe remainder. Only then announce.
Optional send-as after inbound is boringly green.
Rollback: put the screenshot back. You can only roll back if you kept it.
Step-by-step setup / decision path
- Export and reconcile the sheet. Mark role versus personal versus dead.
- Confirm plan limits: aliases, domains, seats. Upgrade before cutover if needed.
- Create all live aliases on MailerZ. Do not create obvious dead spam addresses.
- Lower TTL at least a TTL period before the cut if you still can.
- Screenshot old MX and NS.
- Publish exclusive MX. Delete leftovers.
- Probe a sample of ten including billing and support.
- Probe the rest in batches. HOLD stays on. Write misses. Close with a full pass.
Dead aliases you still publish become future HOLD noise or junk. Retire them in the sheet, not after customers mail them.
If TTL was already a week and you cannot wait, say so. Some resolvers will be late. That is leftover MX by cache, not by record.
Keep the sheet as the source of truth after the move. The next hundred will be easier.
Failure modes and proof
MX before map: 550 storm. Proof: history of unknown recipients.
Dual MX: split mail. Proof: public two owners.
Incomplete export: missing billing@. Proof: a vendor invoice bounce.
Self-send sample: false confidence. Proof: customers fail.
FORWARD to hide misses: junk. Proof: random local-parts.
No screenshot: cannot roll back. Proof: memory versus production.
Wrong NS panel: records never published. Proof: public lookup.
Send-as on cut day: mixed incident. Proof: AUTH in the inbound channel.
Free plan for a hundred aliases: product refuse. Proof: limits.
Shared inbox with no owner: “missing” after 250. Proof: the empty owner column.
Null MX leftover: reject all. Proof: 0 .
Announcing before sample probe: public incident.
MailerZ workflow and product boundary
MailerZ is custom-domain aliasing and forwarding with optional paid send-as. Secuno LLC operates mailerz.net. The app is mail.mailerz.net. Not Workspace, not IMAP, not an open relay, not a campaign ESP.
Envelope SRS only. Header From, Subject, Date, Message-ID, body, and MIME stay intact. Exclusive MX. Hold unknown on Free. Copy SMTP host, port, and TLS or STARTTLS from the dashboard when you send. Do not invent 587 or 465 as MailerZ facts.
Free: one domain, three aliases, one seat, fourteen-day store, fifty outgoing a month, no send-as. Solo forty dollars a year, fifteen aliases, ninety-day store, one hundred outgoing, five send-as per hour. Starter eight monthly or eighty yearly. Business nineteen or one hundred ninety. Agency thirty-nine or three hundred ninety. Quote the pricing page. No SOC 2, ISO, HIPAA, SLA, or inboxing percentage.
Migration planner and docs are the hubs. Agency plan exists for multi-domain volume. Quote pricing. Do not invent seat math.
Cost, alternatives, and trade-offs
A week of sheet work is cheaper than a week of missing invoices.
Workspace migration of a hundred mailboxes is a different, larger project. Do not conflate it with alias routing.
Agencies should price inventory as a line item. That is the work.
TTL waiting is cheap calendar time. Dual MX is expensive mail loss.
Retiring dead aliases reduces future HOLD review cost.
A dress rehearsal on one domain costs a Free plan and teaches the cut.
Rollback screenshots are free. Not having them is not.
Do not buy a second forwarder as insurance. Buy a complete sheet.
Sheet hygiene for a hundred aliases
Normalize local-parts to lowercase. Email local-parts can be case-sensitive in theory and are a mess in practice. Your sheet should pick a convention and stick. Duplicates with different case are how two people own the same role.
Mark each row live, dead, or unknown. Dead rows do not get created. Unknown rows get a human decision before MX day. Creating everything “just in case” is catch-all with extra steps.
Destinations need a working test. A typo in a Google Group address will 550 after a perfect MX cut. Send a test to the destination as itself before you attach it to an alias.
Role rows need an owner column. Support without an owner is a 250 into a mailbox nobody opens. That will be reported as a failed migration.
Personal aliases that belong to ex-staff should be retired or remapped before the cut. Migrating a ghost is how customers reach nobody and you inherit a privacy problem.
Confirm plan alias limits before you import. A hundred aliases is not Free. Quote Solo, Starter, Business, or Agency from the pricing page. Do not invent unlimited.
Batch probes in tens, not in a hundred-wide spray. You will miss a fail in a flood. Fix the class after each batch.
Keep send-as off the cutover day. A hundred inbound aliases plus AUTH debugging is two projects. Schedule SMTP for the next business day.
If the old host’s export is a PDF, budget archaeology. Clicking around a control panel is still cheaper than missing billing@.
After the move, the sheet remains the source of truth. The next hire should not discover aliases by grepping the website.
Rehearse on one domain if the team has never cut MX. Free exists for that rehearsal. Pride is not a runbook.
Rollback is the old MX screenshot. Practice saying that in the kickoff so nobody proposes dual MX as rollback.
A hundred names is a sheet, not a catch-all
How to migrate 100 email aliases safely starts with a sheet, not a catch-all toggle. Columns: local-part, dest mailbox the company can keep, whether send-as is required, last known leftover host, last probe subject, status. Create every named alias on MailerZ before you publish exclusive MX. Exclusive MX only. Delete leftover Google, Microsoft, Cloudflare routing, or registrar hosts. Dual-publish is split brain. Priority numbers are an order, not load balancing. Save the old MX set as text for rollback.
Capacity is a card, not folklore. Free is three named aliases. Solo is fifteen. Starter is fifty. Business is two hundred. Agency is five hundred. Confirm the live pricing page. A “hundred aliases” job is Business or Agency before the cut, not after fifty leftovers hit hold. Catch-all forward is not a free mint of the other fifty. Hold unknowns on everyday production. Review the store. Promote a leftover only when a real person used it. Paid forward belongs to a dated cutover.
Lower TTL at the answering nameservers if you can wait the previous TTL. Print NS first. A registrar tab that does not answer is a silent sheet. Query 8.8.8.8 and 1.1.1.1 after the cut. Agreement on exclusive MailerZ MX is hop one. Agreement on a leftover means you are not done. Waiting a week does not delete a leftover. Probe from a mailbox that is not the destination. Self-send from Gmail to the same Gmail can hide a split.
Sample first: role aliases plus one deliberately unknown local-part to confirm hold. Then the rest in batches with unique subjects. History should show accepted then forwarded for named aliases. Empty history on a named alias is leftover MX or a dest you never mapped. Empty history on the unknown is hold working. Do not flip catch-all because the sample unknown was held.
Do not buy a seat per alias
MailerZ is not IMAP. Destinations stay Gmail or Outlook. A hundred aliases are routing rules, not a hundred hosted mailboxes. Buy a suite seat only if someone needs a hosted store and Calendar. A suite MX next to MailerZ MX is leftover. Exclusive one owner. Envelope SRS only. Header From, Subject, Date, Message-ID, body, and MIME stay intact.
Send-as is a second hop. Creating inbound aliases does not approve outbound. Catch-all does not mint a From. Free cannot finish send-as. Copy the dashboard host, port, and TLS pair together. Set From to an identity you created. Unauthorized send is 550 / 550 5.7.1. Do not paste one SMTP secret into a hundred sites. Agencies: one credential per client zone. Confirm /pricing for hourly and monthly outgoing ceilings. This hop is not a campaign sender.
A hundred-row cut that failed at leftover MX
An agency imported ninety-seven aliases, published MailerZ MX, and left Workspace as “backup.” Half of senders still hit Google. History looked random. The sheet was not the bug. They deleted the leftover, waited two resolver views, re-probed a sample of ten, then the rest. Rollback used the saved MX text when a wizard restored Google the next morning. Recheck after wizards.
A second cut used catch-all instead of the sheet. Harvest plus two dests trained spam. They turned hold back on, named the real leftovers from the store, and probed those only. Unlimited-alias marketing would not have saved a missing list.
Related: features, aliases and catch-all, troubleshooting, migration planner, docs. RFC 5321. Not SOC 2. Not HIPAA. Fourteen-day Free store and ninety-day paid store are recovery for hops this layer saw, not an archive. If counsel wants eDiscovery, buy eDiscovery.
Sign-off for a large alias cut
Sheet complete. Card fits the count with headroom. Aliases created before MX. Exclusive MX both views. Leftovers gone. Sample probe including hold. Full probe. Old MX text saved. Send-as out of scope or paid identities tested once. No shared SMTP across clients. Start free only on a domain you can break. Sign in if the zone already lives here.
Offboard later means delete MX you own, revoke SMTP, and stop forwarding leftovers into an agency inbox. Review quarterly or after a nameserver move. The next physical action is fill the sheet and print public MX, not another tab. That is how to migrate 100 email aliases safely.
If a dest is full, history can show forwarded then dest 4xx. Fix quota. New subject. Do not delete the alias. Do not roll back MX for a full mailbox. If dest files spam, record the folder. Classify is hop four. We do not promise Primary. Caps are not an inbox SLA.
Batch probes without duplicate subjects
A hundred unique subjects beat one subject retried a hundred times. History becomes searchable. Dest search becomes searchable. Number the batches: roles first, people second, leftovers from the old host third. Do not probe during mixed MX. Do not probe by mailing yourself from the dest Gmail. If a batch shows empty history, stop the batch. Print MX. You have leftover or the wrong NS, not a bad local-part.
Shared dests need dest-side labels, not extra MX. Three company inboxes can absorb a hundred roles if the map is printed. Twenty personal Gmails will fail the first vacation. Remap dests to company stores before the cut. Seats on MailerZ are dashboard access, not dests. Confirm /pricing for alias and seat ceilings. Agency exists so the sheet can be long. It does not replace the sheet.
Rollback is exclusive old MX, not mixed. If you must roll back, wait the current TTL, print two views, tell senders the window. Mixed Google plus MailerZ during rollback is the same random delivery you left. Save the old set as text so rollback is typing, not memory.
TTL: lower at answering NS, wait old TTL, cut, delete leftovers, two views, probe, raise TTL. Wizards restore leftovers. Recheck. Domain Connect helpers stay nofollow when cited. Related: troubleshooting, docs, migration planner, aliases and catch-all.
Send-as after the hundred
Inbound first. Then paid identities only for roles that must send. Copy pairs per zone, not one fleet secret. Hourly caps are on the card. Do not discover them with a WooCommerce export. Envelope SRS only. Header From stays on inbound. Unauthorized send is 550. Start free on a breakable domain to learn the sheet. Sign in if the zone already lives here. That is how to migrate 100 email aliases safely without catch-all theater.
If dest 4xx on a batch, fix quota, new subjects, do not roll back MX. If dest spam, record folders, do not add a second MX. Classify is hop four. Not an inbox SLA. Not SOC 2. Not HIPAA. Store windows are recovery.
Old host export versus the live list
An export from Workspace or a registrar forwarder is a starting sheet, not truth. People already use leftovers that never made the export. After exclusive MX and hold, read the store for leftovers a real person used. Promote those. Do not promote harvest. Confirm /pricing if promotions blow the alias ceiling. Business is two hundred. Agency is five hundred. Solo is fifteen — a hundred-row job does not fit Solo.
Parallel old and new MX is not a safe hundred-row strategy. It is mixed owners. Cut exclusive. If you need a dated parallel, the dest mailbox is the parallel, not two MX owners. Related: how to run old and new providers, leftover MX, troubleshooting. Probe sample, then full. Unique subjects. Other mailbox. Empty history stops the batch.
Offboard a client after a hundred-row cut: delete MX you own, revoke SMTP, stop dest forwards into the agency inbox. Do not leave catch-all on. Start free only to learn the sheet on one domain. Sign in if the zone already lives here. Envelope SRS only. Header From stays. Not IMAP. Not an inbox SLA. Not SOC 2.
Sign-off line
Sheet, card, aliases before MX, exclusive both views, leftovers gone, sample including hold, full unique probes, old MX text saved, SMTP split per client if an agency. If a line is blank, do not announce the domain. Confirm /pricing. That is how to migrate 100 email aliases safely.
Unknowns during the cut week
Keep HOLD the entire cut week. A harvest the night you go exclusive will fill dests if you forwarded unknowns. Review the store daily for real people. Promote those rows only. Do not promote admin@ guesses. If the store shows a leftover a customer used, add it to the sheet and probe it the same day. Unique subject. Other mailbox. Confirm /pricing if the sheet now exceeds the card. That extra fact is how to migrate 100 email aliases safely without a dest flood.
FAQ
- What is the safest way to migrate many email aliases?
- Sheet every local-part and destination. Create them on MailerZ before MX. Exclusive MX only. Sample probe, then full probe. Keep the old MX screenshot for rollback. Do not dual-publish.
- Does this require a new mailbox?
- No. Destinations stay Gmail or Outlook. MailerZ is not IMAP. Do not buy a seat per alias.
- Will it work with Gmail or Outlook?
- Yes as destinations. Watch shared inboxes and group addresses in the sheet. Self-send is not the probe.
- What DNS records are involved?
- NS, exclusive MX, verification TXT. Lower TTL beforehand if you can wait. One SPF if you send after cutover.
- What should I test before production?
- A sample of role aliases plus a deliberately unknown local-part to confirm HOLD. Then the rest.
Key takeaways
- Inventory before MX.
- Parallel map on MailerZ, then exclusive cutover.
- HOLD during the move.
- Sample probe, then full probe.
- Screenshot is rollback.
- No dual MX.
- Plan limits before the date.
- Send-as waits until inbound is dull.
Conclusion
A hundred aliases move safely when the sheet is honest and MX has one owner. Everything else is ceremony.
Start free on a rehearsal domain, then cut the real map when the sequence is boring.