Ionos
IONOS SE is a leading German web hosting and cloud services provider, founded in 1988 as 1&1 Internet and rebranded to IONOS in 2018, specializing in digital solutions for small and medium-sized businesses (SMBs) across web presence, productivity tools, and infrastructure.[1][2] With headquarters in Montabaur, Germany, the company operates as a subsidiary of United Internet AG and serves over 6.5 million customers (as of September 2025) in 18 markets worldwide, making it Europe's largest hosting provider.[3][1][4][5] As a one-stop digital partner, IONOS offers a comprehensive portfolio including domain registration, email hosting, website builders, virtual and dedicated servers, and scalable cloud infrastructure, all hosted in its own data centers across Europe and the United States.[6][7] The company emphasizes innovation for SMBs, supporting their digitalization with reliable, cost-effective tools that enable online presence and business growth, while maintaining a focus on sustainability through operations powered by 100% renewable energy at its facilities.[8] In 2024, IONOS reported revenue of €1.56 billion, reflecting 9.6% year-over-year growth, and for the first nine months of 2025, revenue reached €1.04 billion with 7.8% growth; it employs approximately 4,100 people globally (as of June 2025).[7][9][10][11] IONOS's evolution from an early internet service provider to a public company—listed on the Frankfurt Stock Exchange since its IPO in February 2023—highlights its adaptation to the digital economy, with rapid expansion in cloud services alongside its core hosting business.[6][7] It positions itself as a market leader in European web hosting while pursuing ambitious growth targets, including a 10% compound annual revenue growth rate and an EBITDA margin of around 35% in the medium term.[7]History
Founding and early years
Ionos traces its origins to 1988, when Ralph Dommermuth founded 1&1 EDV-Marketing GmbH in Montabaur, Germany, initially as a mail-order business distributing software and hardware to make computing more accessible to consumers.[12] The company quickly pivoted toward internet-related services amid the rising popularity of dial-up connections in the early 1990s, offering basic email accounts and online access to support the growing demand for personal computing tools.[13] This foundational focus on affordable IT solutions positioned 1&1 as an early innovator in democratizing internet access for small businesses and individuals in Germany. A pivotal milestone occurred in June 1998, when 1&1 merged with Schlund + Partner, a prominent German web hosting and domain registration provider founded by Achim Weiss, forming the core of what would become the modern Ionos infrastructure.[14] The merger integrated Schlund's expertise in hosting services with 1&1's marketing strengths, enabling expanded offerings in web hosting and domain management while achieving an initial public offering on the Frankfurt Stock Exchange that year to fuel growth.[15] By the late 1990s, this combination had solidified 1&1's role in the burgeoning European internet market, with early international forays into neighboring countries like France and the UK.[16] Entering the early 2000s, 1&1 emerged as Germany's leading web hosting provider, driven by aggressive expansion in broadband and DSL services that attracted millions of users seeking reliable online presence.[2] These developments laid the groundwork for Ionos's later evolution into cloud-focused solutions.[17]Rebranding and global expansion
In 2017, United Internet AG, the parent company of 1&1 Internet, acquired ProfitBricks, a Berlin-based cloud infrastructure specialist, to strengthen its cloud offerings and expand into infrastructure-as-a-service (IaaS) capabilities.[18] This acquisition integrated ProfitBricks' expertise, paving the way for the launch of IONOS Cloud as a dedicated platform for scalable cloud infrastructure shortly thereafter.[19] The strategic merger with ProfitBricks prompted a significant rebranding effort in October 2018, when 1&1 Internet adopted the name 1&1 IONOS to highlight its evolving focus on cloud services while retaining its established web hosting strengths.[2] This initial phase unified the brands under a single identity, introducing enhanced personal consulting services for customers across hosting and cloud products.[14] In January 2020, the company completed its rebranding to simply IONOS, accompanied by a comprehensive website redesign that improved user experience and accessibility, though the core service portfolio remained unchanged.[6] Parallel to these branding changes, IONOS pursued aggressive global expansion, establishing operations in over 10 countries including Germany, France, the United Kingdom, Italy, Spain, Austria, the United States via IONOS Inc., Canada, and Mexico.[20] This international push, building on earlier entries into North American markets, supported steady customer growth, reaching 6.47 million contracts worldwide by mid-2025 and 6.53 million as of September 2025.[21][22] Key milestones in this period included IONOS's 25th anniversary celebration in July 2023, which underscored the company's commitment to innovation in web hosting and cloud solutions for small and medium-sized businesses.[14] The event highlighted two decades of digital infrastructure advancements and positioned IONOS as a leader in supporting SMB digitalization.[23] Additionally, IONOS expanded into platform-as-a-service (PaaS) offerings through its IONOS Cloud platform, enabling developers to build and deploy applications without managing underlying infrastructure, and entered the AI market with initiatives like the AI Model Hub and an expression of interest for an AI Gigafactory in 2025.[24][25][26] In November 2025, IONOS announced plans to sell its AdTech business to further focus on core hosting and cloud services.[5]Corporate profile
Ownership and leadership
Ionos operates as IONOS Group SE, a publicly listed company on the Frankfurt Stock Exchange since its initial public offering in February 2023.[27] The majority ownership is held by United Internet AG, which controls approximately 63.8% of the shares as of September 2025, with the remainder distributed among institutional investors, free float at 31.2%, and minor holdings such as Helikon Investments at 4.2%.[28] The company's leadership is headed by CEO Achim Weiss, who has served in the role since 2018 and brings over 25 years of experience in the internet industry, overseeing overall strategy and product development.[29] Key executives include Dr. Markus Noga as Chief Technology Officer, responsible for technological direction; Jens-Christian Reich as Chief Commercial Officer and Deputy Chairman of the Management Board, focusing on marketing and sales since 2023; Patrik Heider as Chief Financial Officer, effective November 15, 2025, managing finance and human resources (succeeding Britta Schmidt, who held the role since 2021); Hüseyin Dogan as Chief Operating Officer; Dr. Andreas Nauerz as Chief Product Officer since September 2025; and Arthur Mai as Chief Marketing Officer.[29][30] The Supervisory Board, elected until 2028, provides governance oversight and includes Chairman Ralph Dommermuth, a technology industry veteran and founder of United Internet, along with members such as Kurt Dobitsch, who serves on the Audit Committee and contributes expertise in finance and operations.[31][32] Headquartered in Montabaur, Germany, Ionos employs approximately 4,200 people globally across 70 nationalities as of September 2025, supporting operations in web hosting, cloud services, and digital solutions.[6][22] Its U.S. subsidiary, IONOS Inc., is based in Philadelphia, Pennsylvania, facilitating North American market expansion.[33] Corporate governance at Ionos emphasizes sustainable practices and digital transformation tailored to small and medium-sized businesses (SMBs), aligning with its core mission as Europe's leading hosting provider.[34]Financial performance and growth
In 2024, IONOS Group SE reported total revenue of €1,560.3 million, representing a 9.6% increase from the previous year.[35] Adjusted EBITDA for the year rose 15.8% to €452.2 million, with the margin expanding to 29.0%.[9] These results were supported by steady growth in the core Digital Solutions & Cloud segment, which saw revenue increase 11.6% to €1,248.1 million.[9] The company maintained strong momentum into 2025, with first-quarter revenue reaching €446.3 million, a 19.7% year-over-year rise, and adjusted EBITDA climbing 23.8% to €131.0 million.[36] In the first half of 2025, revenue surged 19.1% to €895.0 million, driven primarily by expansions in cloud services and AI-integrated offerings, while adjusted EBITDA grew 23.3% to €268.7 million, achieving a 30.0% margin.[10] Growth continued in the first nine months of 2025, with revenue increasing 10.2% to €1,219.2 million and adjusted EBITDA rising 21.5% to €400.2 million (margin 32.8%), alongside a customer base expansion to 6.53 million (+210,000 from end-2024).[5] IONOS's customer base expanded to 6.32 million by the end of 2024, adding approximately 160,000 customers from the prior year, with a focus on supporting small and medium-sized businesses (SMBs) in their digital transformation.[35] As a leading provider in the European web hosting market, IONOS anticipates sustained expansion in 2025, with the integration of AI tools expected to enhance stability in its AdTech segment.[37] In November 2025, the company announced plans to sell its AdTech business (Sedo GmbH), potentially streamlining operations and focusing on core hosting and cloud growth.[38] Following the strong first-half performance, the company updated its full-year adjusted EBITDA guidance to approximately €530 million, reflecting about 17.3% growth over 2024; this guidance was maintained after Q3 results.[39]Products and services
Web hosting and domain services
Ionos provides a range of web hosting solutions tailored for individuals, small businesses, and larger operations, including shared hosting, virtual private servers (VPS), and dedicated servers. Shared hosting plans are designed for beginners and small websites, offering unlimited websites, bandwidth, and databases on entry-level tiers, with features such as 99.9% uptime guarantee, daily backups, and a free SSL certificate for secure connections.[40] WordPress-optimized plans enhance performance for content management systems, incorporating SSD storage, OPcache for faster loading, a content delivery network (CDN), automated updates to simplify site management, and a WordPress AI Assistant for content generation and customization launched in Q3 2025.[41][42] VPS hosting caters to users needing more control, starting with scalable resources like 1-8 vCPUs, up to 24 GB RAM, and SSD NVMe storage, including root access and a free Plesk license for customization; an additional price adjustment for VPS plans was implemented in October 2025 due to increases in third-party control panel licensing fees, without changes to features.[43][44] Dedicated servers target high-traffic sites and applications, featuring high-performance AMD or Intel CPUs, up to 1 TB SSD-NVMe memory, and flexible per-minute billing for Windows or Linux environments.[45] Complementing these offerings, Ionos includes an AI-powered website builder that generates sites from user inputs, providing over 100 customizable templates for various industries, along with drag-and-drop editing for non-technical users.[46] Domain services enable registration of top-level domains (TLDs) such as .com, .de, and .net, with introductory pricing starting at €0.75 for the first year and free domain inclusion for annual hosting plans.[47] These services come bundled with DNS management tools like Domain Connect for seamless integration, free wildcard SSL certificates, and optional private registration to protect personal data.[48] Pricing for hosting begins at €1 per month for introductory shared plans, scaling to €10 or more for premium options upon renewal, with 2025 adjustments applied at contract renewal dates without altering existing features or configurations.[40] [49] Additional features support comprehensive online presence management, including email hosting with up to 2,000 addresses across plans, offering 2 GB to 50 GB storage per mailbox, IMAP/POP3 access, spam filters, and virus protection.[50] For eCommerce, integrated tools allow creation of online stores with payment gateways (e.g., PayPal, Stripe), shipping calculators, coupon systems, and inventory management, suitable for small to medium retailers.[51] Security measures encompass malware scanning through Site Scan + Repair, which checks up to 500 subpages daily, automatic threat removal, and ransomware protection via MyDefender backups.[52] [53] These elements position Ionos's hosting and domain services as accessible entry points for digital projects, emphasizing reliability and ease of use for non-expert users.Cloud computing and AI tools
IONOS Cloud provides a flexible infrastructure platform designed for scalable virtual data centers, allowing users to configure and deploy resources through the intuitive Data Center Designer tool, which enables the creation of customized environments in minutes.[24] This service supports hybrid cloud architectures, integrating on-premises systems with public cloud resources for seamless workload management.[24] Key components include robust storage and backup solutions, such as Object Storage for handling large data volumes and Cloud Backup for automated, secure data protection across multiple locations.[54] Additionally, Managed Kubernetes offers orchestration for containerized applications as a free service, with users paying only for underlying compute and storage; a new pricing structure for dedicated cores took effect on April 1, 2025, enhancing cost predictability for production workloads.[55][56] In the realm of AI tools, IONOS integrates artificial intelligence to simplify development and deployment for non-experts. The AI-driven website builder generates complete sites, including homepages and subpages, based on minimal user input about business needs, incorporating SEO-optimized content and AI-generated images.[46] Launched in October 2025, AI Model Studio enables fine-tuning of existing large language models using proprietary data without requiring programming knowledge; users upload datasets via a simple interface to customize outputs for specific applications like search result refinement.[57][58] On November 11, 2025, IONOS launched IONOS Momentum, a GDPR-compliant sovereign AI ecosystem targeting SMBs and the public sector in Europe. It combines Momentum Cloud for secure, high-performance AI infrastructure; Momentum Studio for no-code AI app development and model customization; and autonomous AI agents, such as the AI Phone Receptionist for 24/7 multilingual call handling in over 20 languages, to automate business processes and enhance digital operations.[59][42] Complementing these, a July 2025 integration with Pulumi allows DevOps teams to manage IONOS Cloud resources through infrastructure-as-code, streamlining deployments with familiar programming languages.[60] Core features of IONOS Cloud emphasize scalability and compliance, particularly for European users. The Compute Engine delivers vCPU-based virtual servers with adjustable performance for diverse workloads, ensuring high availability through redundant data centers in Germany, the UK, and the US.[61] A Private Container Registry provides secure, GDPR-compliant storage for Docker images, accessible internationally while maintaining data localization options.[62] Support for Red Hat OpenShift enables enterprise-grade container platform deployments on IONOS infrastructure, offering improved scalability for application orchestration.[63] These elements underscore IONOS's focus on European data sovereignty, with all EU-hosted services adhering to strict regulatory standards for data residency and privacy.[62] Primarily targeting small and medium-sized businesses (SMBs) as well as developers, IONOS Cloud and AI tools serve as an accessible entry point beyond basic web hosting, empowering users to scale from simple sites to complex AI-enhanced applications.[46] In 2025, IONOS advanced its AI infrastructure ambitions by submitting an Expression of Interest in June to the European Commission, in partnership with HOCHTIEF, for an AI Gigafactory project; this initiative seeks EU funding to build a high-performance computing facility with over 50,000 GPUs, operational by 2027, to bolster sovereign AI capabilities across the continent.[64][65]Innovation and initiatives
Research and development efforts
IONOS has prioritized research and development in green computing, emphasizing energy-efficient data centers to reduce environmental impact while maintaining high performance. The company invests in advanced cooling systems, renewable energy integration, and optimized hardware to lower power consumption across its infrastructure. For instance, its Worcester, UK, data center incorporates onsite solar power, covering approximately 10% of energy needs, and is recognized as one of IONOS's most sustainable facilities.[66] Additionally, through participation in the EU's Important Project of Common European Interest on Cloud Infrastructure and Services (IPCEI-CIS), IONOS develops solutions for energy-efficient data center operations and workload management, aligning with broader European goals for sustainable digital infrastructure.[67] A significant aspect of IONOS's R&D involves the development of platform-as-a-service (PaaS) offerings for AI model fine-tuning, launched in the German market in October 2025. The AI Model Studio enables users to customize generative AI models using their own data without requiring programming expertise, facilitating improved accuracy for business-specific applications. This tool builds on IONOS's AI infrastructure, supporting seamless integration with cloud resources for scalable fine-tuning processes.[57][58] Key projects underscore IONOS's commitment to sustainable cloud innovation, including the 2024 Integrated Computing Continuum initiative. This framework integrates cloud, edge, fog, and far-edge computing to optimize resource allocation and minimize energy waste, promoting a holistic approach to green IT. By leveraging energy-efficient hardware and dynamic workload distribution, the initiative enhances overall system sustainability without compromising latency or reliability.[68] IONOS also advances container technologies through enhancements to Kubernetes, providing managed clusters with automated deployment, integrated persistent storage, and optimized resource scaling to support DevOps workflows efficiently.[55][69] On November 11, 2025, IONOS launched IONOS Momentum, a sovereign AI ecosystem designed for small and medium-sized businesses (SMBs) and the public sector. This GDPR-compliant platform integrates AI model fine-tuning, hosting, and productivity tools to support digital sovereignty and innovation.[70] IONOS maintains dedicated R&D teams focused on cloud-native technologies, evidenced by the 2025 release of the IONOS Cloud provider for Pulumi, an infrastructure-as-code tool that streamlines DevOps automation. This provider allows programmatic management of IONOS resources, accelerating development cycles for scalable applications. These efforts have resulted in improved system scalability, enhanced security through automated updates and isolation, and active contributions to open-source cloud tools, including integrations with platforms like Kubernetes and Pulumi.[60][71][9]Digital sovereignty and partnerships
IONOS has emphasized digital sovereignty through its network of EU-based data centers, which ensure data remains within European jurisdiction to mitigate dependencies on U.S.-based cloud providers and comply with regulations like the GDPR.[72] In 2025, the company expanded this infrastructure with a new 8,000 sqm facility in Frankfurt, strategically located near the DE-CIX internet exchange to enhance connectivity and sovereignty.[73] IONOS operates multiple data centers across Europe, including in Germany, the UK, France, and Spain, providing full control over data without foreign access risks.[74] In June 2025, IONOS's Chief Technology Officer, Dr. Markus Noga, addressed scalability concerns for sovereign clouds, asserting that the company possesses sufficient spare capacity to support Europe's shift away from U.S. hyperscalers without performance compromises.[75] Noga highlighted that IONOS's infrastructure is designed for rapid expansion, positioning it as a viable option for organizations prioritizing data independence amid geopolitical tensions.[75] Key partnerships underscore IONOS's commitment to sovereignty. In May 2025, IONOS joined a consortium with SAP, Deutsche Telekom, and Schwarz Group to bid for EU funding to build an AI data center in Germany, focusing on sovereign infrastructure.[76] Separately, on June 20, 2025, IONOS and HOCHTIEF submitted an Expression of Interest to the European Commission for an AI Gigafactory, aiming to create a high-capacity, EU-controlled facility for AI workloads.[64] These collaborations leverage IONOS's cloud expertise alongside partners' strengths in construction and software to advance Europe's technological autonomy.[77] The InterNetX Domain Summit 2025, hosted by IONOS's subsidiary, featured discussions on digital sovereignty, including EU domain regulations and encryption innovations to protect online identities.[78] Experts at the event emphasized policy frameworks for data protection, with takeaways on integrating sovereignty into domain management practices.[79] IONOS supports sovereignty through initiatives like GDPR-compliant tools, including Storage as a Service for secure data archiving entirely within EU boundaries.[80] The company provides checklists and plugins for website operators to ensure compliance, such as cookie consent management.[81] In collaborations for open-source standards, IONOS co-developed the Sovereign European Cloud API (SECA) with Aruba and Dynamo in March 2025, establishing an open interface to reduce vendor lock-in and promote interoperability.[82] Additionally, a June 2025 partnership with Nextcloud launched a sovereign alternative to Microsoft 365, featuring GDPR-compliant open-source office tools hosted on IONOS infrastructure.[83] These efforts position IONOS as a leading European alternative to U.S. hyperscalers, offering cost-effective, scalable options with up to 50% lower pricing while maintaining sovereignty.[24] Events in 2025, such as the Sovereign Cloud Day in Frankfurt, highlighted policy implications, reinforcing IONOS's role in Europe's digital resilience.[84]Sustainability
Environmental commitments
IONOS has maintained climate neutrality for its data center operations since 2008 through a combination of sourcing renewable energy and offsetting unavoidable CO2 emissions.[85] This approach evolved to include 100% renewable electricity across all data centers by 2019, supplemented by onsite photovoltaic generation producing 2.1 GWh in 2024 at three of its nine facilities.[66] As part of its broader IONOS 2030 Climate Strategy, the company aligns with the Science Based Targets initiative (SBTi) to limit global warming to 1.5°C, committing to net-zero emissions by 2050 while targeting a 55% reduction in data center carbon emissions from 2019 levels by 2030.[86][66] In its data centers, IONOS implements practices focused on resource efficiency and waste minimization, achieving 96.2% reuse or recycling of waste in 2024.[66] Operations are supported by energy-efficient hardware, free air cooling systems, and LED lighting, resulting in a Power Usage Effectiveness (PUE) of 1.39 in 2024—an improvement from 1.52 in 2019.[66] The company has eliminated reliance on fossil fuels for primary power, transitioning backup diesel generators to biofuels, which reduce lifecycle emissions by 90% compared to traditional diesel, while maintaining Scope 1 and 2 emissions at 2,507.6 tCO2-eq in 2024.[66] Expansions prioritize low environmental impact, such as avoiding water-intensive cooling to achieve a Water Usage Effectiveness (WUE) of 0.003 liters per kWh—far below the industry average of 0.362.[66][87] All IONOS hosting and cloud services are powered by 100% renewable energy, ensuring green hosting without additional costs to customers.[87][66] The 2024 sustainability report highlights ongoing CO2 neutralization efforts, including certified environmental management systems across all data centers to drive continuous improvements in energy and emissions metrics.[66]Social responsibility pillars
Ionos structures its sustainability efforts around four pillars: Planet, People, Digital Responsibility, and Customer, with the Planet pillar addressing environmental impacts such as emissions reduction, while the remaining three emphasize human, ethical, and client-oriented dimensions.[66][88] The People pillar prioritizes employee well-being, diversity, and inclusive practices. Ionos supports flexible hybrid and remote work arrangements to enhance work-life balance and reduce commuting emissions.[66] The company employs individuals from 74 nationalities, with women comprising 31.3% of the workforce and 24.9% of management positions, alongside an adjusted gender pay gap of 2.4%.[66] To promote fossil fuel-free commuting, Ionos aims for 100% electric vehicle carpool usage by 2030, achieving 11.9% adoption in 2024.[66] Additionally, Ionos invests in employee development, delivering 40,167 hours of training in 2024, with plans for expanded programs in 2025 covering sustainable practices and AI literacy to foster long-term societal contributions.[66] Partnerships like the one with AfB have recycled 450 tons of IT equipment over three years, creating employment opportunities for people with disabilities.[88] Under the Digital Responsibility pillar, Ionos emphasizes ethical technology deployment, data privacy, and cybersecurity. The company has established guidelines for AI usage, including regular audits to detect and mitigate biases in algorithms, with 51.9% of employees completing AI training in 2024.[66] Data privacy is upheld through full GDPR compliance and an 84% coverage of its Information Security Management System.[89] To advance digital inclusion, Ionos participates in community programs such as the GAIA-X initiative for European data sovereignty and the SIMPL project to aid small and medium-sized businesses (SMBs) in digital transformation.[66] Furthermore, collaborations with organizations like Techimpact provide cybersecurity education and technology access to underserved communities.[66] The Customer pillar centers on reliable support for SMBs, Ionos's primary clientele. Through its Personal Consultant program, the company delivers tailored guidance to enhance digital capabilities, analyzing 324,840 pieces of customer feedback in 2024 to improve service reliability and satisfaction.[66] These efforts align with Ionos's commitment to empowering SMBs for sustainable growth.[88] Progress across these pillars is integrated into Ionos's annual sustainability reports, with the 2024 edition adhering to European Sustainability Reporting Standards (ESRS) S1 and S4 to assess and report long-term societal impacts.[66] The 2025 report will continue this framework, building on ongoing initiatives to measure ethical and social outcomes.[66]Challenges and criticisms
Service reliability issues
Ionos has experienced several notable service reliability issues over the years, primarily involving infrastructure disruptions and external attacks that affected web hosting and cloud services. A prominent example occurred in April 2019, when a server outage at a key data center led to widespread downtime lasting approximately one day, impacting customer websites and applications without immediate communication from the provider.[90] These early incidents highlighted vulnerabilities in Ionos's hosting infrastructure, often resulting in temporary unavailability of services and prompting user complaints about recovery times. In 2025, Ionos encountered multiple operational hiccups, particularly in its support and network systems. On September 30, 2025, an outage at one of the company's main offices caused extended delays in hotline services, leading to prolonged wait times for technical support inquiries.[91] This was followed by a minor incident on November 3, 2025, where similar office-related disruptions again increased support line hold times, though on a smaller scale. More critically, on October 29, 2025, an unintended route advertisement error in the IONOS Cloud network at the FR7 data center (located in the DE/FRA metro region) at 12:30 UTC resulted in traffic disruptions, causing packet loss and connectivity issues for cloud-hosted services.[92][91][93] These 2025 events led to temporary downtime for web hosting and cloud computing services, with users reporting spikes in complaints via platforms like Downdetector, particularly around login failures, email access problems, and overall service unavailability. The impacts were most acute for small and medium-sized businesses relying on Ionos for continuous operations, resulting in brief interruptions to websites and applications. Ionos responded promptly to these incidents, resolving the October 29 network issue within hours through network reconfiguration and traffic rerouting, while the September and November support disruptions were fixed by restoring office operations, returning wait times to normal levels. Following these events, the company implemented enhancements to monitoring and stability protocols, including rolling out performance improvements to prevent recurrence of similar routing errors in its cloud infrastructure.[92]Email security configuration problems
Users of IONOS email services have encountered challenges with Sender Policy Framework (SPF) configurations, particularly involving the default record that includes mechanisms likeinclude:_spf.perfora.net for European domains or include:_spf-us.ionos.com for U.S.-based ones.[94][95] This default setup, enabled automatically for IONOS-hosted domains, aims to authorize outbound mail servers but often fails authentication checks when emails are sent to providers like Gmail or Outlook, leading to rejection or marking as suspicious.[95] The primary causes include the presence of multiple SPF TXT records in the domain's DNS zone, which exceeds the recommended limit of one record per domain and triggers "too many lookups" errors during validation, as well as integration errors when combining IONOS with third-party services such as Microsoft 365 or Google Workspace.[95][96]
Common problems reported with these configurations manifest as emails consistently landing in spam folders or experiencing outright delivery failures, particularly noticeable in interactions with major email providers.[95] Invalid SPF records result in the receiving server deeming the sender unauthorized, thereby flagging or blocking messages to mitigate phishing risks.[97] These issues have persisted into 2024 and 2025, with IONOS documentation highlighting ongoing troubleshooting needs for SPF-related authentication failures during email setup and delivery.[98] For instance, when IONOS domains are linked to Microsoft 365, the absence of a properly merged SPF record—including both IONOS and Microsoft mechanisms—can cause systematic bounces or spam routing for outbound emails.[96]
To resolve these configuration problems, IONOS recommends consolidating all SPF mechanisms into a single TXT record per domain, ensuring it lists only essential includes such as the IONOS default alongside any third-party ones (e.g., include:spf.protection.outlook.com for Microsoft 365), and ending with a soft fail qualifier like ~all.[95][96] Users should also enable complementary protocols like DomainKeys Identified Mail (DKIM) for message signing and Domain-based Message Authentication, Reporting, and Conformance (DMARC) to specify handling of failed authentications, which can be configured directly in the IONOS control panel under DNS settings.[99][100] IONOS provides built-in verification tools within its domain management interface to test SPF record propagation and validity, typically requiring up to 48 hours for DNS changes to take effect.[95]
In a broader context, SPF protocols are designed to combat email spoofing and reduce overall spam volume by verifying sender IP authorization, yet misconfigurations in services like IONOS can inadvertently expose users to delivery vulnerabilities or heightened scrutiny from receiving servers.[97] As of 2025, IONOS has emphasized enhanced email authentication integrations, including DKIM support for Microsoft Exchange introduced starting October 24, 2025, to address persistent configuration gaps alongside SPF.[101]