Summary
Identifying companies sharing your email sending IP involves leveraging several tools and strategies. Reverse IP lookups, reverse DNS records, and specialized online tools can reveal domains associated with the IP. Monitoring IP reputation using services like Sender Score and Talos is crucial for gauging the impact of shared IP neighbors, especially considering the increasing trend of IP-based blocking, particularly in the EU. A good ESP should be transparent about shared IPs. If concerns persist, upgrading to a dedicated IP is an option. Furthermore, checking an IP's DNS history and monitoring blacklists can offer insights into past and present associations, including potentially problematic senders. Finally, authentication is paramount and some argue can negate the concerns of shared IPs.
Key findings
- Reverse IP Lookup & DNS: Reverse IP lookups and DNS records can identify domains associated with your sending IP.
- Reputation Monitoring: Tools like Sender Score and Talos help monitor IP reputation and potential negative impacts from shared IPs.
- EU Blocking Trends: IP-based blocking is on the rise, particularly in the EU, making reputation monitoring even more crucial.
- ESP Transparency: A reputable ESP should be transparent about who shares your IP.
- DNS History and Blacklists: Checking DNS history and blacklist status can reveal problematic senders or past associations with your IP.
- Authentication: Proper authentication may mitigate the risks associated with shared IPs.
Key considerations
- Proactive Monitoring: Regularly monitor your IP's reputation and blacklist status.
- ESP Selection: Choose a transparent and reputable ESP.
- Dedicated IP: Consider a dedicated IP if shared IP concerns persist.
- EU Focus: Pay special attention to IP reputation when sending to the EU.
- Authentication Setup: Ensure proper authentication (SPF, DKIM, DMARC) is set up, regardless of shared IP status.
What email marketers say
10 marketer opinions
Several methods exist to identify companies sharing your email sending IP address. Reverse IP lookups can reveal associated domains, while deliverability monitoring platforms and online 'shared IP neighbors' tools can display co-users. ESP transparency is key; a good ESP should disclose who shares your IP. Regularly checking IP reputation and blacklist status can indicate issues stemming from other senders. If concerned, upgrading to a dedicated IP is an option. Examining an IP's DNS history can reveal past associations.
Key opinions
- Reverse IP Lookup: Tools exist to identify domains associated with a given IP address, potentially revealing co-users.
- ESP Transparency: Reputable ESPs should be transparent about other users sharing your IP address.
- Deliverability Platforms: Deliverability monitoring platforms can expose other senders on a shared IP through spam trap networks.
- Online Tools: Various online tools can identify 'neighbors' or co-users on a shared IP address.
- IP Reputation: Monitoring IP reputation is crucial as the actions of others on a shared IP can impact your deliverability.
- Blacklist Checks: Blacklist status can indirectly indicate problematic users sharing your IP.
- DNS History: Checking an IP's DNS history can highlight dodgy domains that have previously used that IP.
Key considerations
- ESP Quality: If using a reputable ESP with proper authentication, shared IPs may be less of a concern.
- Proactive Monitoring: Regularly check your IP's reputation and blacklist status to identify potential issues early.
- Dedicated IP: Consider upgrading to a dedicated IP for greater control over your sending reputation.
- Data Privacy: ESPs may have privacy restrictions that prevent them from fully disclosing information about other users on a shared IP.
Marketer view
Email marketer from SparkPost Blog shares that using a shared IP address can expose your email sending reputation to the activities of other senders on that IP. Monitoring IP reputation is important.
3 Nov 2024 - SparkPost Blog
Marketer view
Email marketer from Gmass says if you are worried about the IP reputation of others, that you should upgrade to a dedicated IP
11 Jun 2025 - Gmass
What the experts say
5 expert opinions
Experts recommend several methods to check which companies share your email sending IP. SenderScore.org and reverse DNS lookups can reveal associated domains. Monitoring IP reputation with tools like Sender Score or Talos provides insight into IP health and potential impacts from other users. There's an increasing trend of IP-based blocking, especially with EU providers, indicating the importance of monitoring shared IP environments.
Key opinions
- SenderScore.org: SenderScore.org can reveal domains sharing your IP address.
- Reverse DNS Lookup: Performing a reverse DNS lookup identifies domain names associated with your IP.
- IP Reputation Monitoring: Monitoring your IP's reputation helps understand its health and potential issues from shared IP users.
- EU Blocking: IP-based blocking is increasing, particularly with EU providers.
Key considerations
- EU Focus: Pay close attention to IP reputation and blocking if sending to the EU.
- Proactive Monitoring: Actively monitor IP health with available tools to identify issues promptly.
- Tool Variety: Utilize a combination of tools, including SenderScore.org and reverse DNS lookups, for a comprehensive view.
Expert view
Expert from Email Geeks shares that senderscore.org can sometimes reveal other domains sharing an IP address. He suggests plugging the IP into senderscore.org to see associated domains.
28 Jan 2023 - Email Geeks
Expert view
Expert from Spam Resource, John Levine, explains that you can perform a reverse DNS lookup on your IP address. This will show you the domain names associated with that IP, which can help you identify other entities sharing it.
18 Aug 2022 - Spam Resource
What the documentation says
4 technical articles
Technical documentation emphasizes that monitoring IP reputation is critical for email delivery to major providers like Gmail and Outlook. Reverse DNS records and reverse IP lookup tools are valuable for identifying domains associated with a given IP address, enabling identification of entities sharing the IP.
Key findings
- IP Reputation Importance: Monitoring IP reputation is crucial for email delivery to Gmail and Outlook.
- Reverse DNS Records: Reverse DNS records help identify domain names associated with an IP address.
- Reverse IP Lookup Tools: Reverse IP lookup tools display domain names hosted on a specific IP.
Key considerations
- Tool Utilization: Use reverse DNS records and reverse IP lookup tools to identify IP sharing.
- Delivery Impact: Low IP reputation can negatively affect email delivery, especially to major providers.
- Proactive Monitoring: Regularly monitor IP reputation to address potential issues.
Technical article
Documentation from DigitalOcean explains that reverse DNS records (PTR records) can be used to identify the domain names associated with an IP address, helping determine who else might be using the same IP.
8 Feb 2023 - DigitalOcean
Technical article
Documentation from MXToolbox explains that their reverse IP lookup tool can show you all the domain names that are hosted on a particular IP address.
5 Sep 2022 - MXToolbox
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