Comparison
Jan 22, 2026
CEO and co-founder
Maildoso for Agencies: Best Practices, Optimization Tips & Avoiding Common Pitfalls
Understanding the shared IP architecture
Shared IP pools work like a carpool lane where you are affected by other drivers. When you share an IP address with other senders, someone else's bad behavior can damage your reputation without you even knowing it.
The noisy neighbor problem
The noisy neighbor effect occurs when one sender's performance drops because another sender on the same infrastructure consumes too many resources or sends spam. In email infrastructure, if a single sender uses a disproportionate amount of resources or sends spam, overall deliverability suffers for everyone on that IP.
Here is what this means for your agency:
- Pooled reputation risk: Your deliverability depends on every other sender using the same IP
- Blacklist exposure: Emails sent from blacklisted IPs rarely reach inboxes, and recovery can take weeks or months
- No control: You cannot prevent other senders from damaging the IP reputation you share
The contrast with dedicated infrastructure is stark. As covered in our video on dedicated vs shared IPs, dedicated IPs mean your sending behavior alone determines ESP trust. You own your reputation completely.
Why shared pools require constant vigilance
With shared infrastructure, you cannot "set and forget" your email setup. You need active monitoring because:
1. IP rotation is unpredictable: Dynamic IP rotation means your sending reputation changes based on who else is using your pool that day
2. No isolation: A single bad actor spamming gets the whole IP range flagged
3. Delayed feedback: You often learn about problems via angry client calls, not proactive alerts
Technical setup and DNS configuration
Manual DNS configuration is where shared infrastructure costs you time. Every domain needs SPF, DKIM, and DMARC records configured correctly before you can send a single email.
Step-by-step DNS setup process
Here is what manual configuration requires for any cold email infrastructure:
1. SPF (Sender Policy Framework):
Add a TXT record that authorizes every service sending on your domain. The format looks like: `v=spf1 include:spf.protection.outlook.com ~all`
2. DKIM (DomainKeys Identified Mail):
Generate a key pair in your email platform and publish the public key as a TXT record at `selector._domainkey.yourdomain.com`. This authenticates your domain for the From address.
3. DMARC:
Add a TXT record at `_dmarc.yourdomain.com`. Google recommends starting with `p=none` plus a reporting address, then moving to quarantine or reject after confirming all sources pass alignment.
Critical timing: You should wait 48 hours after adding SPF and DKIM records before enabling DMARC so authentication can propagate across the internet.
Maildoso-specific configuration steps
If you are using Maildoso's platform, here is the specific workflow:
1. Domain connection: Navigate to Settings > Domains and add your domain. Maildoso will display the required DNS records.
2. Manual DNS entry: Copy each SPF, DKIM, and DMARC record into your domain registrar (GoDaddy, Namecheap, Cloudflare). Wait 24-48 hours for propagation.
3. Verification: Return to Maildoso dashboard and click "Verify DNS Records." If verification fails, use Mail-Tester to troubleshoot.
4. Inbox provisioning: Create inboxes under Accounts > New Account. Note that you are assigned to a shared IP pool automatically with no option to request dedicated IPs on standard plans.
5. Warmup configuration: Maildoso does not include native warmup, so you need to integrate external warmup tools via IMAP/SMTP credentials.
This process repeats for every domain you add, which is why the time cost compounds as you scale.
The time cost calculation
Manual setup takes approximately 15-20 minutes per domain when everything goes smoothly. For 50 domains, that is potentially 12+ hours of DNS panel work. Add in troubleshooting propagation issues and verification, and you are looking at significant time investment on technical setup alone.
Compare this to automated infrastructure. As shown in our 2-minute setup tutorial, we configure SPF, DKIM, and DMARC automatically with zero manual DNS work.
What automated setup looks like
With our platform, the domain setup process works like this:
1. Purchase domains through the platform or transfer existing domains
2. Platform auto-configures all DNS records in seconds
3. Create unlimited inboxes with IMAP/SMTP credentials
4. Export to CSV and import to your sending platform
"Compared to other ESP providers, using Inframail kinda feels like magic. As soon as you start the process of creating email accounts, it will automatically start adding all the records for you, and show the process in real-time." - Verified user review of Inframail
Inframail currently has 38 5-star reviews on Trustpilot, reflecting its reliability for high-volume senders.
Domain rotation and warmup strategies
On shared infrastructure, domain rotation is not optional. It is your primary defense against reputation contamination from other senders.
Domain rotation best practices
No single domain lasts forever in cold email. Plan to cycle through multiple domains over time, keeping an eye on performance and retiring domains that show signs of decline before they tank your sender reputation.
Here is the math for scaling:
Daily Email Target | Inboxes Needed | Domains Needed | Reasoning |
|---|---|---|---|
500 | 10-17 | 5-8 | 30-50 emails per inbox daily |
1,000 | 20-34 | 6-7 | 2-3 inboxes per domain |
2,500 | 50-84 | 15-20 | Rotate to spread reputation risk |
Best practice is to stick to 30-50 emails per inbox per day and rotate across multiple domains to scale while staying under the radar. These rotation rates apply to shared infrastructure like Maildoso where IP reputation is pooled. With dedicated IPs, you can often push higher volumes per domain once warmed properly.
Warmup sequencing
Warmup is non-negotiable for cold email. The email warm-up process takes 4-8 weeks to reach maximum deliverability potential according to Microsoft's guidance on achieving maximum deliverability. All sender domains should be properly warmed before performing any type of engagement.
Warmup timeline:
1. Week 1: Start with 5-10 emails per day to engaged recipients
2. Week 2: Increase to 15-20 emails per day
3. Weeks 3-4: Scale to 15-25 per inbox daily
4. Week 5+: Gradually increase based on engagement metrics
For guidance on warmup after migrating infrastructure, see our warmup migration guide.
Because Maildoso does not include native warmup, you need to export your IMAP/SMTP credentials and connect them to an external warmup service. This adds another vendor to manage and additional monthly costs per inbox.
The warmup tool question
Maildoso does not include native warmup in standard plans. You will need external tools like Warmbox ($15-50/month per inbox) or similar services. This adds to your total cost of ownership and requires managing another vendor relationship.
"InfraMail makes it remarkably easy to purchase domains, configure them correctly, create inboxes, and initiate warm-up immediately. The level of automation is exceptional and clearly designed for serious operators." - Verified user review of Inframail
Managing deliverability on shared infrastructure
Active monitoring is the only way to survive on shared IPs. You need systems to catch problems before clients notice.
Maildoso monitoring workflow
Maildoso provides basic sending metrics in the dashboard, but you need external tools for comprehensive deliverability monitoring:
1. Check Mail-Tester scores weekly for each domain (manual process)
2. Monitor bounce rates in your sending platform (Instantly, Smartlead), not in Maildoso
3. Check blacklist status using MXToolbox or similar (Maildoso does not include automated blacklist monitoring)
4. Track inbox placement using seed lists or third-party tools
The lack of integrated monitoring means you are often reacting to problems rather than preventing them.
Monitoring your sender reputation
Use Mail-Tester to check your email score regularly. Your goal should be to score 9-10/10 on Mail-Tester according to their FAQ recommendations. We score 9.5/10 on Mail-Tester testing across our infrastructure.
Key metrics to track according to our campaign health guide:
- Inbox placement rate: Target 75-85%+ inbox rate
- Bounce rate: Keep under 2% or providers start flagging campaigns
- Spam complaints: Major providers enforce strict thresholds (0.3% max)
Common pitfalls that tank shared IP deliverability
Watch for these mistakes that cause deliverability drops on platforms like Maildoso:
1. Skipping warmup: Sending cold from new domains triggers spam filters immediately
2. Exceeding 50 emails per inbox daily: Aggressive sending on shared IPs accelerates blacklist risk
3. Not monitoring blacklists: You often learn you are blacklisted only when clients complain
4. Ignoring bounce rates: Bounce rates over 2% signal bad list data and damage shared IP reputation faster
5. Mixing client campaigns on single domains: One client's aggressive campaign can burn domains used by other clients
On shared infrastructure, these mistakes do not just hurt your campaigns. They hurt everyone on your IP pool.
Condition-based campaign management
Segment your traffic based on domain health. When you notice a domain declining:
1. Reduce send volume immediately
2. Check blacklist status
3. Rotate that domain out of active campaigns
4. Begin warmup on replacement domains
The redirect problem
Email Service Providers track where your links redirect. If they see suspicious patterns, deliverability drops. On shared infrastructure like Maildoso where you have less control over IP reputation, redirect patterns matter even more. Our help docs explain the difference between normal redirects and phantom redirects and how to hide domain redirects from ESPs.
Email verification protects sender score
Always verify your email lists before sending. Bad data (bounces, spam traps) accelerates reputation damage on shared IPs. Use verification tools to clean lists and protect your sender score.
For a complete walkthrough on improving deliverability, watch our guide on actually getting cold emails delivered.
Cost analysis: Maildoso vs Google Workspace vs Inframail
The sticker price on shared infrastructure is misleading. True cost includes platform fees, domain costs, warmup tools, sending platforms, and your time.
Total cost of ownership breakdown
Cost Component | Google Workspace | Maildoso (Shared IP) | Inframail |
|---|---|---|---|
Platform (50 inboxes) | $420/month | $100-150/month | $129/month |
Domain costs | Self-managed | $16.44/year each | $16.44/year each |
Warmup tools | Not needed | $750-950/month* | External required |
Setup time (50 domains) | Variable | 12+ hours | 10-30 minutes |
IP type | N/A | Shared pool | 1-3 dedicated |
- Warmup cost calculation: 50 inboxes × $15-19/month per inbox for external warmup tools = $750-950/month ongoing cost
Monthly TCO for 50 inboxes
Google Workspace: ~$420/month (predictable, no additional tools needed)
Maildoso: ~$150/month platform + ~$750-950/month warmup + 12+ hours labor = $900-1,100/month ongoing (first month higher due to setup labor)
Inframail: $129/month platform + ~$68.50/month domains ($16.44 * 50 / 12) = $197.50/month before warmup.
The Inframail FAQ covers our pricing structure and what is included.
The hidden cost: founder time
Every hour you spend on DNS configuration is an hour not spent on sales calls. At $100/hour founder time, significant manual setup represents real opportunity cost that does not appear on any invoice.
Scale economics
The gap widens as you scale. At 200 inboxes:
- Google Workspace: $1,680/month
- Maildoso: Platform cost increases + warmup for more inboxes + more firefighting time
- Our flat rate: Still $129/month whether you run 50 or 200 inboxes
"I personally have over 1,000 email accounts with Inframail for one flat price. Adding all those records would have probably taken dozens of hours. Instead all records were added within 10 minutes." - Verified user review of Inframail
To calculate your specific needs, use our email sending capacity guide.
When to graduate from shared pools to dedicated IPs
Shared infrastructure works at small scale. The math changes when you are managing real client volume.
Switch triggers
Consider dedicated infrastructure when:
1. Domain count exceeds 50: Manual DNS management becomes unsustainable at this scale
2. Client deliverability complaints increase: Shared IP issues are affecting retention
3. Infrastructure costs consume margin: You need cost control to protect profitability
4. Operational overhead blocks growth: Time spent firefighting could go to sales
What dedicated IPs provide
Dedicated IP infrastructure means your sending reputation stays isolated. Unlike Maildoso's shared pools where one bad sender can damage your deliverability, dedicated IPs mean your behavior alone determines your reputation. According to IP comparison research, dedicated IPs are safer because you are the only user, reducing the risk of being blacklisted by others' behavior.
Our Agency Pack includes 3 dedicated US-based IPs at $327/month. The Unlimited Plan includes 1 dedicated IP at $129/month.
Microsoft partnership credibility
We built our platform on Microsoft's cloud infrastructure with reputable IPs. The enterprise partnership announced in January 2024 provides infrastructure credibility that shared pool providers cannot match.
"Inframail was recommended to me by a friend over two years ago. I've been using them ever since. Don't look back. Pretty solid deliverability compared to other platforms I've used in the past." - Verified user review of Inframail
The upgrade path
Moving from shared to dedicated infrastructure follows this process:
1. Calculate your current effective TCO (platform + warmup + labor)
2. Map your domain count and daily send volume
3. Start with 10-20 domains on the new platform as a pilot
4. Migrate domains in batches, maintaining warmup throughout
5. Export credentials to your existing sending platform (Instantly, Smartlead)
For a complete setup walkthrough, watch our Ultimate Cold Email Infrastructure Guide or the step-by-step InfraMail setup tutorial.
Making the right choice for your agency
Shared IP infrastructure like Maildoso works if you are running under 25 domains, have time to manage manual DNS configuration, can tolerate occasional deliverability fires, and are comfortable with significant setup work per batch of domains.
Dedicated infrastructure works if you are managing 50+ domains, your margins are under pressure from infrastructure costs, you need predictable deliverability for client retention, or you want to spend your time on sales instead of DNS configuration.
"Inframail has been absolute gold in terms of delivering a great customer experience, and allowing me to spin up cold email infrastructure at scale for my clients as easily and fast as possible." - Verified user review of Inframail
For agencies serious about scaling cold outreach, the math favors dedicated IPs and automation. Sign up to Inframail and get started today.
Frequently asked questions
Does Maildoso include warmup?
Maildoso does not include native warmup tools in standard plans. You need external services like Warmbox ($15-50/month per inbox), adding $750-950/month for 50 inboxes to your total cost.
What is the difference between shared and dedicated IPs?
Shared IPs pool reputation across multiple senders, meaning one bad actor affects everyone. Dedicated IPs isolate your reputation so only your sending behavior determines deliverability.
How long does manual DNS setup take for 50 domains?
Manual SPF, DKIM, and DMARC configuration takes approximately 15-20 minutes per domain plus 48-hour propagation wait. For 50 domains, expect significant setup time investment.
Can I use shared infrastructure for agency cold email?
Yes, but it requires strict domain rotation (30-50 emails per inbox daily), external warmup, and active monitoring. The operational overhead increases significantly at 50+ domains.
What is Inframail's pricing for unlimited inboxes?
Our Unlimited Plan costs $129/month and includes 1 dedicated US-based IP with unlimited email inboxes and automated DNS setup.
Key terms glossary
Shared IP pool: A group of IP addresses used by multiple senders simultaneously. Your deliverability depends on everyone else's sending behavior.
Dedicated IP: An IP address exclusively used by one sender. Your sending behavior alone determines ESP trust and reputation.
DNS propagation: The time it takes for DNS changes (SPF, DKIM, DMARC records) to update across the internet. Typically 24-48 hours for full propagation.
TCO (Total Cost of Ownership): The complete cost of running email infrastructure, including platform fees, domain costs, warmup tools, sending platforms, and labor hours.
Email warmup: The process of gradually increasing sending volume on new domains and inboxes to build positive reputation with email providers. Takes 4-8 weeks minimum.
Noisy neighbor effect: When one sender's bad behavior on a shared IP pool degrades deliverability for all other senders using that same IP range.
