What Happens If an IP or Domain Underper- forms?

February 12, 2026

This is where managed infrastructure actually shows its value. It’s not about what happens when everything works. It’s about what happens when something breaks.

Early Detection Through Continuous Monitoring

We’re monitoring bounce codes, rejection patterns, placement trends, and gateway signals continuously. This is active monitoring, not passive logging. We’re not just collecting data. We’re analyzing it in real time to detect deviations.

If an IP’s bounce rate shifts noticeably in a day, we see it. If a domain’s placement rate drops unexpectedly, we catch it. If rejection patterns change, we notice the delta. These aren’t just metrics we track. They’re signals we interpret.

This matters because infrastructure problems don’t announce themselves. They degrade gradually. By the time you notice them, damage is done. Your reputation is declining and you don’t know why.

Here’s a real scenario: Your IP starts getting throttled by Gmail. On day one, it’s subtle. Some sends get rate-limited. You don’t notice. By day three, it worsens. By day five, Gmail is rejecting a significant amount of your traffic. By the time you notice your bounce rate spiked, you’ve already lost a week of sends and your reputation is damaged.

With continuous monitoring, we catch changes immediately. We see the trend before it becomes a crisis. We’re not waiting for your metrics to flash red. We’re watching the amber signals and acting on them.

Immediate Replacement Without Pausing Your Sends

Here’s the critical part: when we detect underperformance, we don’t say “we’re going to investigate and get back to you in 48 hours.” We replace the IP immediately. No waiting. No deliberation.

If an IP starts showing signs of declining reputation, we move your traffic to a different IP. You don’t pause. You don’t reschedule. Your sends continue from proven infrastructure while we investigate the underperforming IP. Your outreach program doesn’t skip a beat because your infrastructure team is fixing something.

This requires redundancy in the infrastructure. We maintain backup IPs specifically for this scenario. When one IP starts degrading, we have a ready replacement. It’s like having spare tires, not just one tire. More costly to maintain, but you never get stranded.

This is expensive. It requires more infrastructure than you technically need. But it’s what it takes to guarantee delivery continuity. You never hit a wall where your outreach pauses because an IP got blacklisted.

Compare this to self-managed infrastructure: Your IP gets reputation-banned. You discover it after three days of degraded performance. You scramble to get a new IP set up. Meanwhile, you’ve lost a week of sends and disappointed your sales team. With managed infrastructure, your sends continue while we handle the replacement behind the scenes.

Subdomain Architecture Isolates Problems

Our multi-subdomain architecture is designed specifically to isolate problems. If one subdomain starts showing issues, it doesn’t drag down your entire sending. Problem isolation is the whole point.

Let’s say you have four subdomains:
sending.company.com
outreach1.company.com
outreach2.company.com
outreach3.company.com

If sending.company.com starts underperforming (maybe one of its IPs got reputation issues), we shift traffic to the other subdomains. The problem is isolated. Your other three subdomains continue performing normally while we investigate and fix sending.company.com.

This is different from having one domain and watching it slowly decline. With one domain, problems compound and eventually hit a breaking point. You can’t isolate them. One IP reputation issue affects all your sends from that domain.

With multiple subdomains, problems are compartmentalized. A reputation issue in one subdomain doesn’t cascade to the others.

Proactive DNS Audits Prevent Degradation

We also audit your DNS setup periodically. We’re not looking for things that are broken. We’re looking for things that are creeping toward broken. Prevention, not reaction.

Maybe an SPF record has too many includes and is approaching a technical limit. Maybe your DMARC policy could be tighter. Maybe there’s a small inconsistency in your DKIM that doesn’t cause failures now but could under stress. Maybe you have obsolete DKIM keys still published that should be rotated.

Periodic audits catch these edge cases. We tighten them up before they become problems.

Example: Your DKIM key is from 2021. It’s still working fine. But ISP standards are moving toward stronger key sizes. We proactively rotate it to a newer, stronger key before it becomes a deliverability issue. You never hit a wall where filtering gets stricter because your DKIM is outdated.

This is why we audit even when nothing has changed. The ISP landscape changes. Filtering standards evolve. What was acceptable a year ago might be risky now. Periodic audits keep you current. Your DNS setup is always aligned with current best practices, not yesterday’s standards.

Investigation of Anecdotal Issues

Beyond quantitative monitoring, we also investigate anecdotal spam reports. If you mention that some recipients are reporting your emails as spam, we take that seriously. Not as noise. As a signal.

We don’t dismiss it as random complaints. We look at whether there’s a pattern. We check whether a specific domain or subdomain is getting flagged. We investigate whether there’s a coherence issue in your sending.

Maybe you mention that three recipients at a specific company reported your emails. We investigate: Is it just those three or is that company broadly filtering you? Is it a domain issue or an IP issue? Is it specific content or infrastructure?

This is detective work, not algorithmic monitoring. But it’s how you catch issues that metrics alone would miss. Sometimes the data looks fine but anecdotal feedback suggests a problem. That’s a clue. We dig into it.

The Result: Reliability Without Micromanagement

The point of all this is that you don’t have to manage infrastructure. You don’t have to monitor bounce codes or check IP reputation or worry about DNS. We do that. You focus on your campaigns.

You get infrastructure that works, stays working, and fixes itself before you notice there’s a problem. That’s the promise. Managed infrastructure means you never have to wonder if your delivery is slipping. We’re watching. We’re fixing problems before they impact your program.

Your job is to write good emails and target the right people. Our job is to make sure they land.

We’d love to learn more about your business, email deliverability and outreach goals, and see if we might be able to help.

Whether you have questions about what we do, how Protocol works, or you’d just like to pick our brains on some of our best practices, we’d be happy to chat.

Schedule a call with our Revenue Director, Chrisley Ceme.

Talk To Chrisley

This is where managed infrastructure actually shows its value. It’s not about what happens when everything works. It’s about what happens when something breaks.

Early Detection Through Continuous Monitoring

We’re monitoring bounce codes, rejection patterns, placement trends, and gateway signals continuously. This is active monitoring, not passive logging. We’re not just collecting data. We’re analyzing it in real time to detect deviations.

If an IP’s bounce rate shifts noticeably in a day, we see it. If a domain’s placement rate drops unexpectedly, we catch it. If rejection patterns change, we notice the delta. These aren’t just metrics we track. They’re signals we interpret.

This matters because infrastructure problems don’t announce themselves. They degrade gradually. By the time you notice them, damage is done. Your reputation is declining and you don’t know why.

Here’s a real scenario: Your IP starts getting throttled by Gmail. On day one, it’s subtle. Some sends get rate-limited. You don’t notice. By day three, it worsens. By day five, Gmail is rejecting a significant amount of your traffic. By the time you notice your bounce rate spiked, you’ve already lost a week of sends and your reputation is damaged.

With continuous monitoring, we catch changes immediately. We see the trend before it becomes a crisis. We’re not waiting for your metrics to flash red. We’re watching the amber signals and acting on them.

Immediate Replacement Without Pausing Your Sends

Here’s the critical part: when we detect underperformance, we don’t say “we’re going to investigate and get back to you in 48 hours.” We replace the IP immediately. No waiting. No deliberation.

If an IP starts showing signs of declining reputation, we move your traffic to a different IP. You don’t pause. You don’t reschedule. Your sends continue from proven infrastructure while we investigate the underperforming IP. Your outreach program doesn’t skip a beat because your infrastructure team is fixing something.

This requires redundancy in the infrastructure. We maintain backup IPs specifically for this scenario. When one IP starts degrading, we have a ready replacement. It’s like having spare tires, not just one tire. More costly to maintain, but you never get stranded.

This is expensive. It requires more infrastructure than you technically need. But it’s what it takes to guarantee delivery continuity. You never hit a wall where your outreach pauses because an IP got blacklisted.

Compare this to self-managed infrastructure: Your IP gets reputation-banned. You discover it after three days of degraded performance. You scramble to get a new IP set up. Meanwhile, you’ve lost a week of sends and disappointed your sales team. With managed infrastructure, your sends continue while we handle the replacement behind the scenes.

Subdomain Architecture Isolates Problems

Our multi-subdomain architecture is designed specifically to isolate problems. If one subdomain starts showing issues, it doesn’t drag down your entire sending. Problem isolation is the whole point.

Let’s say you have four subdomains:
sending.company.com
outreach1.company.com
outreach2.company.com
outreach3.company.com

If sending.company.com starts underperforming (maybe one of its IPs got reputation issues), we shift traffic to the other subdomains. The problem is isolated. Your other three subdomains continue performing normally while we investigate and fix sending.company.com.

This is different from having one domain and watching it slowly decline. With one domain, problems compound and eventually hit a breaking point. You can’t isolate them. One IP reputation issue affects all your sends from that domain.

With multiple subdomains, problems are compartmentalized. A reputation issue in one subdomain doesn’t cascade to the others.

Proactive DNS Audits Prevent Degradation

We also audit your DNS setup periodically. We’re not looking for things that are broken. We’re looking for things that are creeping toward broken. Prevention, not reaction.

Maybe an SPF record has too many includes and is approaching a technical limit. Maybe your DMARC policy could be tighter. Maybe there’s a small inconsistency in your DKIM that doesn’t cause failures now but could under stress. Maybe you have obsolete DKIM keys still published that should be rotated.

Periodic audits catch these edge cases. We tighten them up before they become problems.

Example: Your DKIM key is from 2021. It’s still working fine. But ISP standards are moving toward stronger key sizes. We proactively rotate it to a newer, stronger key before it becomes a deliverability issue. You never hit a wall where filtering gets stricter because your DKIM is outdated.

This is why we audit even when nothing has changed. The ISP landscape changes. Filtering standards evolve. What was acceptable a year ago might be risky now. Periodic audits keep you current. Your DNS setup is always aligned with current best practices, not yesterday’s standards.

Investigation of Anecdotal Issues

Beyond quantitative monitoring, we also investigate anecdotal spam reports. If you mention that some recipients are reporting your emails as spam, we take that seriously. Not as noise. As a signal.

We don’t dismiss it as random complaints. We look at whether there’s a pattern. We check whether a specific domain or subdomain is getting flagged. We investigate whether there’s a coherence issue in your sending.

Maybe you mention that three recipients at a specific company reported your emails. We investigate: Is it just those three or is that company broadly filtering you? Is it a domain issue or an IP issue? Is it specific content or infrastructure?

This is detective work, not algorithmic monitoring. But it’s how you catch issues that metrics alone would miss. Sometimes the data looks fine but anecdotal feedback suggests a problem. That’s a clue. We dig into it.

The Result: Reliability Without Micromanagement

The point of all this is that you don’t have to manage infrastructure. You don’t have to monitor bounce codes or check IP reputation or worry about DNS. We do that. You focus on your campaigns.

You get infrastructure that works, stays working, and fixes itself before you notice there’s a problem. That’s the promise. Managed infrastructure means you never have to wonder if your delivery is slipping. We’re watching. We’re fixing problems before they impact your program.

Your job is to write good emails and target the right people. Our job is to make sure they land.

Our Revenue Director, Chrisley Ceme, is leading the Triggered Outbound program.Chrisley’s gone deep on this strategy and can walk you through:

  • How Triggered Outbound fits with your outbound goals
  • What triggers are available (and what’s possible within our platform)
  • Pricing, onboarding, and getting started
Talk To Chrisley

Senders Case Studies

See All Case Studies

Momofuku

Founded by chef David Chang, Momofuku is a renowned culinary brand with a nation-wide presence, including restaurants and an online store with delicious goods. They ran into an issue with their email sending – high bounce rates and blocked sending. With hundreds of thousands of people on their email lists eager to stay informed, and an impeccable reputation to uphold, Momofuku wanted to nip this problem in the bud quickly.

  • Momofuku reached out to Senders to run a diagnostic test on their sending infrastructure and find the root cause
  • Senders deliverability experts discovered an issue with their DMARC, which was preventing emails from being sent, as their WordPress wasn't aligned with their SPF
  • Senders provided the most effective solution helping Momofuku restore safe sending, and suggested next steps to ensure everything keeps running smoothly on their end
  • The client reported that Senders helped identify the problem and got them back on track 

Andrew Yeung

Where many others see a problem, Andrew sees an opportunity. His work may center around product leadership at Google (and previously Meta), but his true calling is all about bringing brilliant change-makers together.

How it started: Andrew hosted small-scale dinners for a handful of people at the peak of the pandemic in NYC, to enable safe connections during the most isolating times. How it’s going: His events now count as many as 2,000 tech leaders each, and he has set up 100+ such parties for more than 15,000 people in the past couple of years. Andrew understands that if two minds are better than one, putting two thousand together, preferably in the same room, can make a profound difference.

Given the impact of his community-building efforts, people want him to be able to reach out – and email is often the best way to do so. So, we helped out a bit.

  • Andrew came across deliverability issues that prompted him to get in touch with Senders and look into the best possible solutions
  • The Senders team made the necessary domain configuration adjustments, with a focus on the domain’s email authentication settings to enhance security and deliverability
  • The SPF record was updated to include “Brevo” (Sendinblue) to strengthen authentication and reduce the chance of landing emails into spam
  • The DMARC policy update enabled better readability of DMARC reports for human analysts, which is essential for preventing email spoofing and phishing
  • Senders fixed the missing DKIM setup with Google, so that it now shows the email hasn’t been tampered with in transit
  • As a result, the client now has better, more stable email deliverability and security

Myrina.ai

Stands out as a trailblazer in empowering women entrepreneurs through technology and a supportive community.

Myrina.ai offers a cutting-edge range of AI-powered SaaS marketing and sales tools that cater specifically to female entrepreneurs and women-led businesses. Myrina.ai enables users to automate marketing and sales, while helping them scale their authentic selves while saving time and boosting conversions. Their Myrina’s Army community fosters a supportive platform that champions female entrepreneurs and their values, empowering them to conquer barriers and achieve their business goals. The company's dedication to providing not only top-notch technological solutions but also a platform for networking and mentorship underscores their commitment to fostering success among women in the entrepreneurial space.

Naturally, they wanted to make sure their email sending infrastructure was set up correctly to protect their reputation and successfully reach their recipients. Our deliverability team worked with the client’s team on:

  • Aligning the client’s three domains with Amazon to make sure they are compatible and optimized in order to integrate with Amazon’s system
  • Setting up a proper DMARC policy to protect their domains against unauthorized use and phishing scams
  • Enhancing email deliverability as well as security, so that each email sent from these domains can be properly authenticated and more likely to land in the right inbox
  • As a result, the client can protect the reputation of their business and domains, while safely sending out their email campaigns

Physician’s Choice

Sometimes the sheer number of options of any product can be daunting – how on earth do you pick the right one? This is especially true with supplements, as we can find them just about anywhere, but we can rarely understand a third of the ingredients listed. Unlike most, Physician’s Choice provides supplements with pure, potent ingredients that work. No fillers or “proprietary” blends with unidentified ingredients. They do the research, so you don’t have to.

  • The client’s team spotted issues with DMARC failures in Google Postmaster
  • The Senders deliverability team worked with the client to update the DMARC configuration to enable report collection
  • The client is now able to obtain detailed reports to diagnose the exact causes of the failures and prevent them in the future with proper DMARC setup