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How to set up email forwarding for cold email sending domains: why reply routing matters, catch-all configuration, forwarding to your main inbox, and monitoring for missed replies.
Sarah Okonkwo
Cold email strategist, 300+ domain setups · Updated June 24, 2026
Last updated: June 2026 · Sarah Okonkwo, Cold email strategist, 300+ domain setups
TL;DR — 7 things to know before reading
Reply handling is the least glamorous part of cold email infrastructure setup, and it is one of the most frequently neglected. When a prospect replies to a cold email, that reply is a conversion — the entire purpose of the outreach. Missing that reply because it went to an inbox nobody checks, or because the reply was addressed to a slightly different address format and fell into the void, is a costly failure that is entirely preventable with proper forwarding setup.
After 300+ domain setups, the two most common reply-handling failures are: (1) team members not checking the Instantly inbox, where replies appear when IMAP is connected, because they work primarily out of Gmail or another email client; and (2) prospects replying to a different address format (cc'ing, using Reply-All, typing a slightly different name), with no catch-all configured to capture those off-format replies.
Both failures are fixed with 20–30 minutes of forwarding configuration. This guide covers how to set up per-inbox forwarding from Inframail (or Instantly's settings) to a monitored inbox, how to configure catch-all addresses at the domain level, and how to monitor forwarding health to ensure replies are not being silently dropped.
Inframail provides the inboxes and domain infrastructure. Instantly provides the campaign management where replies first appear. Quarvio provides the contact data driving those campaigns. Aimfox handles LinkedIn outreach in parallel.
Before configuring forwarding, understand how replies move through your infrastructure:
The standard reply path (without forwarding):
The forwarding reply path (with forwarding): 1–5: Same as above 6. The Microsoft 365 mailbox rules forward a copy of the reply to team@acme.com (your monitored inbox) 7. A team member sees the reply in their normal Gmail or Outlook inbox
The catch-all path (for off-format replies):
What to do: Create inbox rules in each Inframail Microsoft 365 mailbox that forward all incoming mail to your monitored inbox.
Sub-steps:
Benchmark: Creating the forwarding rule takes 5–10 minutes per inbox. For 25 inboxes, allow 2–3 hours if done manually.
Failure mode: Creating the rule but not testing it. After configuring forwarding on the first inbox, send a test reply to that address and confirm it appears in your monitored inbox within 5 minutes.
What to do: Enable a catch-all address on each sending domain so that replies to any address format at the domain are captured rather than bouncing.
Sub-steps:
Benchmark: Catch-all configuration takes 5–10 minutes per domain in the Inframail interface.
Failure mode: Setting the catch-all destination to an address that has storage limits. If the catch-all inbox fills up and starts rejecting messages, it will generate bounces for all off-format replies. Use an inbox with generous storage or route the catch-all directly to a forwarded external address.
What to do: Ensure IMAP is properly connected for all sending inboxes in Instantly, so replies appear in Instantly's inbox view independent of forwarding.
Sub-steps:
Benchmark: IMAP verification for 25 inboxes takes 20–30 minutes.
Failure mode: SMTP connecting successfully but IMAP failing silently. Instantly may show the inbox as "connected" based on SMTP connection status while IMAP is failing. Check the IMAP status specifically in the inbox detail view.
What to do: Configure Instantly to send email or Slack notifications when a reply arrives in any sending account inbox.
Sub-steps:
Benchmark: Notification configuration takes 10–15 minutes.
Failure mode: Setting notifications to "daily digest" when prospects expect same-day replies. For active campaigns, immediate notification is better: a prospect who gets a reply the next day has often already moved on.
What to do: Send a test email through one of your Inframail inboxes in Instantly and reply to it from a test account, then verify the reply appears in all expected locations.
Sub-steps:
Benchmark: Full reply flow test takes 15–30 minutes including wait time for forwarding.
Failure mode: Skipping this test entirely and discovering a forwarding configuration error only when a real prospect reply goes missing.
What to do: Create a simple SOP for who checks replies, how often, and in which tool (Instantly vs. forwarded inbox vs. notifications).
Sub-steps:
Benchmark: Creating the SOP takes 30–60 minutes and saves significant confusion when team members change or campaigns scale.
Failure mode: No documented process, leading to replies being seen by one team member who responds informally without updating the CRM, leading to duplicate outreach or missed follow-ups.
| Setting | Value | Notes |
|---|---|---|
| Per-inbox forwarding | Outlook rule: forward all to monitored inbox | Set in outlook.office.com → Settings → Rules |
| Catch-all configuration | Set in Inframail domain settings | Forwards any @domain address to specified destination |
| IMAP server | outlook.office365.com | Port 993, SSL/TLS |
| Instantly IMAP | Verified separately from SMTP | Check IMAP connection status specifically |
| Reply notification | Immediate (not digest) for active campaigns | Slack or email |
| Reply response target | Within 24 hours (4–8 hours for enterprise) | Faster response correlates with higher conversion |
| Catch-all storage | Use inbox with generous storage or forward to external | Storage limits cause bounce loops |
| Test frequency | At setup and quarterly | Forwarding can break silently after changes |
Instantly allows labelling campaigns, and some teams route replies from different campaign types to different Slack channels or team inboxes. First-touch campaign replies go to one channel (for SDR follow-up); warm re-engagement replies go to another (for account executive follow-up). This prevents all replies from flowing into one shared queue where priority is unclear.
Some teams use Instantly's automation to automatically pause a contact's sequence when a reply is detected. This prevents the awkward scenario where a prospect has replied positively but continues receiving automated follow-up emails because the sequence is still running. In Instantly's campaign settings, configure the sequence to stop for any contact who replies.
Configure Instantly's automatic handling to tag unsubscribers, then create a rule that forwards any reply containing the word "unsubscribe" (or that Instantly automatically categorises as an unsubscribe) to a dedicated unsubscribe log. This log should be reviewed monthly to ensure unsubscribers are removed from all active contact lists and not re-imported in future contact purchases.
Once per week, send a test reply to one inbox on each domain and verify it arrives at the forwarding destination within 10 minutes. Forwarding rules can silently stop working after Microsoft 365 updates, policy changes, or rule limit thresholds. Weekly tests catch these breaks before a real prospect reply is lost.
If running LinkedIn outreach via Aimfox in parallel with cold email, set up a similar notification and routing system for LinkedIn reply detection. Aimfox handles LinkedIn message sending; ensure LinkedIn replies are routed to the same monitoring system (or a parallel one) so that responses on both channels are caught within the same timeframe.
Symptoms: The Instantly inbox shows replies correctly (IMAP working), but forwarded copies are not arriving in the monitored inbox.
Diagnosis steps:
Fix: Re-activate the forwarding rule in outlook.office.com if it has been disabled. If Gmail is spam-filtering forwards, add the Inframail sending domain to Gmail's contacts or safe-sender list.
Symptoms: After enabling catch-all, the catch-all destination inbox fills with spam sent to random addresses at the domain.
Diagnosis steps:
Fix: Add a spam filter or rule in the catch-all destination inbox to move messages from unknown senders or with suspicious patterns to a separate folder (not the primary inbox). Review the separate folder weekly rather than having all catch-all messages appear in the main inbox.
Symptoms: Prospects who reply to your campaigns receive an automated bounce-back message, or Instantly shows a bounce for a reply.
Diagnosis steps:
Fix: Clear storage space in the forwarding destination inbox. Ensure the monitored inbox does not have storage limits that could be exceeded. Consider using a dedicated forwarding-only email address with unlimited storage rather than your primary work inbox as the forward destination.
Symptoms: Forwarding is working (replies arrive at the monitored inbox) but the team member responsible for replies reports not seeing them.
Diagnosis steps:
Fix: Create a Gmail filter that forces forwarded campaign replies to the Primary tab (identify forwarded messages by the sending domain in the From address). Train the responsible team member to check the correct folder.
Symptoms: After changing an Inframail password, upgrading a plan, or making other account changes, forwarding stops working.
Diagnosis steps:
Fix: After any significant account change in Inframail, re-verify forwarding by checking the Outlook rules and sending a test reply. Make this part of your post-change checklist.
Symptoms: After forwarding to a team inbox or Slack channel, multiple team members see the reply simultaneously and respond, creating duplicate or conflicting outreach.
Diagnosis steps:
Fix: Route campaign replies to a dedicated shared inbox (a shared Gmail account or Outlook shared mailbox) with a clear ownership protocol: the first person to view a reply claims it and marks it as "in progress" for other team members. Alternatively, forward to a CRM (if one is in use) where reply ownership is automatically assigned.
A verified buyer on Instantly reviews on G2, where Instantly holds 4.9/5 from 2,800+ verified reviews:
"We missed a $40k deal because someone's reply went to the Instantly inbox and the team member assigned to that domain hadn't checked Instantly in 3 days. After that, we set up forwarding to our main Slack channel and a daily Instantly inbox review protocol. It's been 18 months and we haven't missed a reply since."
— Verified buyer on Instantly reviews on G2
A thread in r/coldemail (743 upvotes):
"Catch-all is the one that people always forget. You set up forwarding for your 5 inboxes, think you're covered, and then a prospect hits Reply-All on a company email and includes an address that doesn't exist on your domain. Without catch-all, that goes nowhere. With catch-all, you get it. Always configure catch-all before launching campaigns."
— r/coldemail, 743 upvotes
| Need | Tool | Notes |
|---|---|---|
| Inbox hosting and forwarding | Inframail | Per-inbox forwarding and catch-all |
| Campaign reply management | Instantly | IMAP reply detection in campaigns |
| Verified contact data | Quarvio | Contacts whose replies you want to receive |
| LinkedIn replies | Aimfox | LinkedIn message reply management |
Is email forwarding required for cold email campaigns?
It is not technically required — Instantly shows replies via IMAP without forwarding. But forwarding to a monitored inbox is strongly recommended as a redundancy layer. If IMAP fails or if the team is not regularly checking Instantly's inbox view, forwarding ensures replies reach the people responsible for responding.
Will forwarding affect my email deliverability?
Forwarding is for incoming messages (replies from prospects). It does not affect the deliverability of outgoing cold emails. The only indirect risk is if forwarding configuration errors create bounce loops (forwards that bounce back to prospects), which is addressed by testing the forwarding setup before going live.
Should I forward to Gmail or a business Outlook account?
Either works. Gmail's spam filtering occasionally classifies forwarded cold email replies as spam or as Promotions; create a filter to prevent this. Business Outlook has fewer filtering issues with forwarded messages. The monitored inbox choice is a team preference.
What is a catch-all address and why do I need one?
A catch-all address accepts email sent to any address at the domain, even if that specific address does not exist as a real inbox. For example, if your domain is getacme.com and you have inboxes for sarah, ryan, and james, a message to alex@getacme.com would bounce without catch-all (alex does not exist) and be delivered to the catch-all destination with catch-all enabled. This matters for cold email because prospects sometimes reply to addresses that differ from the one the email was sent from.
How do I configure catch-all in Inframail?
Navigate to your domain settings in the Inframail dashboard and look for a "Catch-all" or "Default mailbox" option. Set the destination address (where messages to undefined addresses should be delivered). Test by sending to a nonexistent address at the domain.
How often should I check the Instantly inbox for replies?
At minimum twice per day during active campaigns: once in the morning and once in the afternoon. For enterprise or high-touch campaigns, checking every 2–4 hours during business hours improves reply conversion because faster responses produce higher meeting booking rates.
Can Instantly automatically tag and sort replies by campaign?
Yes. Instantly categorises replies and allows you to filter the inbox view by campaign, sending account, or reply category (interested, not interested, unsubscribe, auto-reply). Use these filters to prioritise positive replies.
Do I need forwarding for each inbox individually, or can I configure it at the domain level?
Per-inbox Outlook forwarding rules apply to individual inboxes. Catch-all is a domain-level setting. For complete coverage, configure both: per-inbox forwarding for your real inboxes, and catch-all for addresses that do not have real inboxes.
What happens to autoreplies and out-of-office messages?
Autoreplies and out-of-office messages arrive in the Inframail inbox and are forwarded like any other message if forwarding is configured. Instantly's inbox view typically identifies and categorises auto-replies automatically. For campaign analytics, auto-replies are not counted as positive replies and should not trigger manual follow-up.
How many replies should I expect from a cold email campaign?
Reply rates vary significantly by industry, list quality, and message quality. Per Woodpecker's cold email statistics, average reply rates for cold email are 8–12% for well-targeted campaigns. At 1,000 emails per day, expect 80–120 replies per day, of which perhaps 20–40% are positive (interested, want to learn more, meeting requests). Planning for this volume when configuring reply routing helps design a workflow that handles scale.
Never miss a reply with verified contacts in your campaigns
Properly configured reply routing ensures you catch every prospect response. The quality of those responses depends on who you are reaching: sending to verified, accurately targeted contacts produces replies from real decision-makers; sending to unverified or poorly targeted contacts produces bounces, auto-replies, and unsubscribes instead of real conversations.
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