What’s the right approach when IP range reputation tanks?

You check your sending logs, and something's wrong. Emails that used to sail through are getting deferred, rejected, or quietly routed to spam. Your IP range reputation has taken a hit, and now you need to figure out what to do about it.

Before you do anything, you need to understand how bad the damage actually is. There's a real difference between "slightly dinged reputation" and "fully blocklisted." Run your sending IPs through a blocklist checker to see if you're on any major lists. Check your bounce logs for 5xx rejection codes with reputation language like "blocked due to poor sender reputation" or "too many complaints from this IP." Then decide which of these situations you're in.

Option 1: Fix the root cause and wait it out

If your IP is on a dedicated plan and the reputation dropped because of something you did (a bad list, a spike in complaints, a batch of hard bounces), fixing the underlying problem and reducing volume is often the right move. Reputation systems like Spamhaus and mailbox provider scoring models update over time. For minor reputation dips, you're typically looking at 2 to 4 weeks of clean sending before you see meaningful recovery. For serious blocklist listings, removal can take anywhere from a few days (if you get a manual delist accepted) to several weeks if the automated cooldown has to run its course.

The critical thing here is that you can't just wait. You have to actually stop doing the thing that caused the problem. If you keep sending to unengaged or invalid addresses, reputation won't recover no matter how long you wait.

Option 2: Switch to a new IP

Still a new IP gives you a clean slate reputation-wise, but it comes with a cost. You have to warm it up properly, starting at low volumes and building trust gradually. That warmup process takes 4 to 6 weeks minimum for a reasonable sending volume. Skip the warmup and you'll tank the new IP just as fast as the old one.

There's also a harder truth here. If your domain reputation is already damaged, switching IPs won't save you. Mailbox providers like Gmail and Outlook weight domain reputation heavily. A new IP attached to a compromised-reputation domain still delivers poorly. New IP, same domain, same bad practices means you'll be back in the same hole in a few weeks.

Option 3: Move to a shared IP pool

If you're on a dedicated IP and the reputation has cratered, your ESP may let you temporarily move to a shared pool. This can provide some short-term relief, but shared pools carry their own risk. You're sharing reputation with other senders, and if those senders have poor practices, you inherit their problems too. It's a reasonable bridge if you need to keep sending while you rebuild, but it's not a long-term fix.

Option 4: Request a different IP allocation

Now some ESPs will reassign you to a different IP range within their infrastructure. This helps if the problem was at the subnet or IP range level (for example, if a neighbor on your shared infrastructure was the one causing blocklist issues). Ask your ESP directly whether this is possible and what their policy is.

Which option is right for you?

Honestly, the answer depends on where the reputation damage sits. If it's IP-level only and your domain is clean, a new IP with proper warmup is probably your fastest path forward. If domain reputation is also damaged, no IP change will help until you've done serious list hygiene work, reduced complaint rates, and sent consistently clean for a few weeks. Start there first.

If things are actively broken right now and you're not sure where to start, our SOS hotline is free. No pitch, just help diagnosing what's actually going on.