Attachment. The closest thing email has to a four-letter word. Blamed for everything from clogging inboxes to enabling hackers…yet we can’t live without them.
How did these digital appendages email users love to hate become so crucial? This complete guide explores the hidden backstory, security balancing act, and productivity supercharging potential of email attachments.
What Is an Email Attachment?
So what exactly constitutes an “email attachment”? In simple terms, an email attachment is any file that gets sent along with an email message, piggybacking on that digital envelope to reach the recipient.
You’ve surely noticed the ubiquitous “Attach Files” button in your email client. Tapping that allows you attach documents, spreadsheets, presentations, images, audio, video files, or anything else on your device to the outgoing message. Attachments are then seamlessly bundled with and embedded into that email.
It’s a bit like placing paperclips, photos, or other items into a physical envelope when mailing something. But digitally!
Definition and Key Functions
More formally, an email attachment refers to any file that is encapsulated as part of a multipart email message per the MIME encoding standard. This bundles the attachment as a distinct data packet, yet connects it to the main body of the email.
The key functionality email attachments enable is easily sharing files and digital content directly within emails, instead of needing separate channels. Any file type can be attached, sent, and received with just a few clicks.
So fundamentally, email attachments provide:
- A conduit for rapidly sharing documents and media assets via email
- Avoidance of slower, less user-friendly transfer methods
- Seamless transmission of files alongside email messages
- Support for virtually any file format type or size
It’s no wonder over 60% of emails today contain at least one attachment given these capabilities!
Common Types of Email Attachments
Because attachments make sending files so seamless, they get used for transporting nearly every conceivable digital asset type via email.
Some of the most common examples of email attachments include:
- Documents: Word files, PDFs, Excel spreadsheets, PowerPoint slides
- Images: Photos, GIFs, logo graphics, pictorial content
- Videos: Training materials, explainer animations, product demos
- Presentations: PowerPoint decks, sales pitches
- Audio files: Podcasts, interviews, music
- Archives: Compressed ZIP folders containing multiple files
- Software installers or marketing materials: Executable MSI installer files, PDF brochures
- Design drafts: Logo options, website layouts, product renderings
As you can see, attachments serve countless collaboration, project management, marketing automation, and general communication functions thanks to their flexibility and ease of use.
Whether you need to send meeting notes to colleagues, share wireframe images with web developers, route product photos for approval, or even just email grandma some cute cat videos – file attachments enable distributing virtually any digital asset via email with a couple of clicks!
A Brief History of Email Attachment Standards
Email attachments didn’t just appear out of nowhere. Their capabilities evolved over decades alongside internet infrastructure and email standards.
Understanding this trajectory helps illustrate why attachments work the way they do today. It’s been a winding journey – but an innovation-filled one!
Early Text-Only Email Systems
In email’s early days, simplistic text-based communication was the norm. The original ARPANET messaging system (early 1970s) strictly allowed only basic letters and numbers.
File attachments were still decades away!
Through the 1970s and into the 80s, standards like UUCP and SMTP provided the backbone to later internet email distribution. But they too only supported 7-bit ASCII text messages.
Still no attachments!
Encodings Allow Binary Attachments
Necessity being the mother of invention, clever workarounds did eventually emerge to allow file sharing via email:
UUencode (1980)** – **Mary Ann Horton pioneered this method of encoding any 8-bit file into a 7-bit ASCII format that could transport binaries.
BinHex (1984) – Enabled Mac users to email document files on early versions of AppleTalk networks.
XXencode (1985) – Similar to UUencode but specifically for MS-DOS files and IBM PC networks.
These encoding schemes worked by taking binary files, converting them into lengthy strings of standard characters, then pasting the output into email message bodies. Not very elegant!
But they did provide a bridge allowing basic documents and files to hitch email rides even on text-only networks.
Modern MIME Standard
Finally in 1992, Nathaniel Borenstein and Ned Freed introduced the MIME standard that unlocked the robust, seamless email attachments we rely on today.
MIME (Multipurpose Internet Mail Extensions) established a universal encoding system allowing virtually any digital file type to be transmitted as an email attachment.
Key MIME capabilities that attachment users take for granted include:
- Multipart packaging bundling attachments with message bodies
- No size restrictions on attachments
- Binary files sent without textual encoding
- Built-in integrity checks and transmission safeguards
- Broad compatibility across email platforms and networks
Officially published as the IETF RFC2045 standard in 1996, MIME instantly unleashed a torrent of document sharing, design collaboration, photo mailing, and attachment behaviors that characterize email productivity archetypes we see today!
Technical Aspects of Sending Attachments
We rely on email attachments seamlessly shuttling documents and files around every day. But behind the scenes, some complex technical gymnastics make this possible.
Understanding a bit about how attachments get packaged, restricted, rerouted, and transmitted can make you a savvier user.
Attachment Size Limits and Encoding Overhead
One key technical challenge is file size. Transferring large attachments requires robust infrastructure.
Yet limits frequently complicate sharing bigger files:
- ISP Restrictions – Most email providers cap attachments at 25MB or less. Gmail and Outlook cut off at 25MB while many business email services default to 10-15MB limits.
- Server Storage – Attachments must stream through multiple mail servers when routing cross-domain. Each caches packets before sending on, necessitating size cutoffs.
- Encoding Bloat – Base64 encoding increases attachment sizes by ~37%. A 20MB file becomes ~28MB when attached. Some servers blocks encoded sizes over 25MB regardless of original file dimensions.
So attempting big transfers often fails. What helps navigate around?
Bypassing Size Limits with Mail Servers
Rather than relying on external email apps, accessing underlying SMTP servers directly provides more attachment flexibility.
Services like Mutant Mail route messages through a secure, privately hosted mail server instead of third-party providers. This hands control back to users, sidestepping artificial attachment restrictions.
With your own IMAP/SMTP server, file size limits can stretch past 100MB in some cases. No more pesky failed transfers or encoding bloat crashes! The server handles it all seamlessly under the hood.
Packaging and Sending the Multipart Message
Once past size restrictions, how do attachments traverse networks uncorrupted?
MIME encoding handles bundling multiple content types into a single message:
- Attachment is converted into base64 format to transmit binary data as ASCII characters
- Multipart container defines boundaries separating message body from attachments
- Integrity checks validate transmission completed fully intact
- Entire message bundle gets routed through mail servers as transit points
- Recipients’ email clients automatically parse and unpack the multipart sections
- User simply clicks to access the smoothly delivered attachment!
So while attachments appear effortless from the user perspective, in reality some sophisticated handling keeps the infrastructure flowing frictionlessly.
Uses and Applications of Email Attachments
At this point, you hopefully have a solid conceptual grasp on email attachments – what they are, how they work, and how the capability has evolved.
But why does any of that matter? What do we actually use attachments for in real-world scenarios?
Understanding common applications reveals why hundreds of billions of attachments traverse networks each year, making them among email’s most ubiquitous and useful features.
File Sharing and Collaboration
Email’s killer app has always been connecting people and enabling collaboration. Attachments supercharge that capability for digital assets.
Virtually any document type gets shared via attachments daily across all industries:
- Office files – Word, Excel, PowerPoint files help teams collaborate on reports, models, decks, and proposals
- Images / Video – Designers route proofs, architects share renderings, filmmakers send cuts
- Code / Data – Developers attach snippets to illustrate issues, analysts share data extracts
“Attaching that report for your review” has become a standard office phrase. This real-time digital distribution channel lets project partners instantaneously access files from email inboxes. Beats the slow paper mailroom shuffle!
Transferring Projects and Media
Entire digital projects also get shared as attachments in creative fields:
- Photographers batch zip final edited images
- Musicians bounce audio mixes and master stems
- Video editors route final video exports
- Writers attach manuscript files or eBook files
Routing hefty batches avoids external file transfers. Attachments enable emailing 100GB of video dailies or 700 product photos as easily as a single JPEG!
Enabling Remote Work
The work-from-home revolution further propelled attachments into the productivity spotlight.
Physically distributing files to dispersed teams proved impossible. So attachments picked up the slack:
- HR shares policies and handbooks with remote staff
- Sales route pricing guides, RFP templates, presentation decks
- Marketing leverages email automation attachments at scale
- Execs attach quarterly reports to distributed leadership
Syncing distributed, hybrid teams relies on easily sharing files through email channels. Attachments help bridge geographic divides.
The takeaway? However you apply them, attachments multiply productivity by avoiding external transfer hurdles. Email’s ubiquity means workplace content flows freely via attached files.
Risks and Security Vulnerabilities
With great power comes great responsibility. Email attachments may enable effortless file sharing, but also open dangerous security holes.
Attachments give cybercriminals an attack vector directly into inboxes. Various schemes deliver malware, steal data, and compromise systems.
But informed users can guard against threats. Let’s break down attachment vulnerabilities users face so you can fortify defenses.
Malware Threats
The most dangerous attachment risk comes from malware payloads. Files or documents transmitted as attachments may secretly harbor viruses, ransomware modules, spyware scripts and other threats that activate upon opening.
Infection often occurs in clever socially engineered ways:
- Expired Invoice Notice – Opens a spreadsheet that installs Formbook password stealing malware
- Salary Charts – Embedded macros in the Excel file run remote access Trojans
- Video Attachment – Media player vulnerability drops cryptomining scripts
Once activated, destructive processes like data encryption, system lockouts, password dumping, and mining cryptocurrency kick off.
Over 30% of cyberattacks now leverage email attachments as an infection method making this a prime infrastructure weak spot.
Phishing Attempts
Closely related are phishing attacks that weaponize attachments. These schemes use social engineering to fool users into enabling threats.
Tactics like impersonating trusted brands or known contacts encourage downloading attached files. For example:
- Email pretending to be from Microsoft SharePoint asking you to verify account access
- Fake internal memo from the HR manager requiring updated contacts list
Such psychological tricks build false trust. Clicking phishing attachment links or enabling content bestows hackers system access to raid data, proliferate attacks on your network, or sell account credentials on the dark web.
In fact, a shocking 91% of breaches start with phishing emails. Dodging deception poses a top priority.
Compromised Accounts
Even legitimate, trusted contacts can accidentally enable threats by sending compromised attachments that infect unintended recipients.
If an account gets infiltrated, hackers can deploy malware to everyone in stolen address books via attachment trojans without raising suspicions.
Such breach scenarios highlight why caution remains essential even when dealing with longtime email partners. Verify attachments even from known reliable sources. A single infected computer can create enterprise-wide devastation.
Guarding Against Attacks
Given myriad risks, how should we protect against attachment-based aggression?
The most potent tools include:
- Enabling Security Scans – Leverage antivirus, anti-spam, sandboxing, and threat detection capabilities in email services to analyze attachments before opening.
- Exercising Caution – Never open unexpected attachments, even from known contacts, before verifying legitimacy. Use alternate confirmation channels.
- Limiting Device Access – Prevent attachments from directly opening into integrated apps that touch secure data. Quarantine files first.
- Authentication Checks – Validate source integrity via domain authentication like DMARC/SPF to confirm no spoofing or impersonation occurred.
With great power comes great responsibility. But armed with aware caution and the right security tools, we can safely harness email attachments powers for productivity…without sweetening the reward for hackers along the way!
Best Practices for Safe Attachment Sharing
While threats exist, everyday attachment use need not resemble walking through a minefield. Applying a few prudent best practices goes a long way.
Think before clicking, confirm recipients, name files clearly, and validate compatibility to keep your sharing both safe and savvy.
Securing Recipients and Sources
Mistakenly misaddressing attachments creates unnecessary risk. A short double check avoids unintended sharing:
- Verify recipients – Before attaching sensitive docs, confirm the recipient list is precisely targeted. No stray CCs getting privileged data!
- Confirm sharing consent – Does this recipient or org expect and agree to this file transfer? Don’t assume; explicitly check sharing is expected.
- Validate known sources – Before opening externally originating attachments, directly confirm with the sender that they intentionally sent this. Eliminate impersonation chances.
These recipient and source checks only take a moment but close security gaps vulnerable to exploits.
Avoiding Delivery Failures
Another easily avoided pitfall involves attachments bouncing or failing delivery through size limits or banned file types.
If attachments don’t arrive intact, productivity gets disrupted. Follow best practices to enable smooth transfers:
- Check size limits – Assess both your email provider and recipient domainrestrictions on attachment file size limits and encoding overhead.
- Compress/chunk large files – For oversized attachments, try selectively sharing portions of documents rather than entire massive files whenever feasible.
- Plan external options – Maintain backup cloud sharing channels as needed if attachments exceed reasonable size limits for users heavily reliant on large file transfers.
With some forethought, you can structure information flows around technical limitations to prevent interrupted delivery.
Descriptive Filenaming Conventions
“Preliminary Budget Draft Revisions.pdf” means far more than just “document.pdf” alone. Clear filenames provide useful organizational context for recipients even before opening the attachment.
Some tips on attaching descriptively named files:
- Clarify content – Have filenames directly state what the attachment contains rather than using vague allusions Openness builds trust in security contexts
- Organize information flows with filenames – “Q4 Financials Report Appendix.xlsx”
- Prevent confusion – Add version numbers to track draft iterations and changes – “Q4 Financials v2_RL.xlsx
Sound attachment naming prevents misunderstandings about expected contents or purposes before users ever open files.
Confirming File Compatibility
A final but critical consideration focuses on actually being able to use attachments. Incompatible formats disrupt workflows.
So always:
- Check software dependencies – Will recipients have apps needed to open this attachment format? Adobe Acrobat, Microsoft Office, CAD programs, and media players comprise some common prerequisite dependencies.
- Provide viewer options for unsupported formats where possible – Share native files but also PDF/JPEG renders for maximum compatibility.
- Convert to universally accessible formats when needed – For wide collaboration, export Office docs to PDF to retain formatting across devices.
Ensuring file type alignment reduces delays from basic incompatibilities. Smooth out usability speed bumps and collaboration hums.
When sharing attachments, a little precaution goes a long way. But don’t let healthy awareness spur overreaction either. Apply balanced wisdom and attachments become an ally rather than adversary!
The Future of Email Attachments
Email attachments unlocked a digital productivity revolution across multiple decades by allowing seamless file sharing via messaging. How might this capability continue evolving moving forward?
Ongoing innovation seems poised to strengthen integration, enhance protection, and accelerate distribution speeds – while preserving the beloved simplicity that makes attachments click.
Tighter Cloud Storage Integration
As both file sizes and security vulnerabilities balloon, attachments may outgrow native email capacity to robustly support transfers.
That’s why industry momentum points toward deeper integration with separate cloud storage platforms.
Instead of acting as file transport mechanism itself, email could pivot to more of addressing and authorization role – empowering linked cloud services to handle heavy attachments behind the scenes.
Gmail already supports Google Drive natively. Other webmail apps integrate with Box, Dropbox, OneDrive and SharePoint.
The trend lines point toward unified workflows that leverage expanded attachment functionality within cloud ecosystems, with emails triggering permissions.
Enhanced Protection Capabilities
Expanding threats will also necessitate email services beefing up native security scanning capabilities related to attachments.
Methods like sandboxed previews, enhanced heuristics, and threat isolation could help strengthen protections:
- Multi-layered static and behavioral detection of potential malware
- Transparent handling with visibility into security queues
- Orchestration with separate security analytics platforms
The stakes around hardening attachment protections will only intensify as more advanced social engineering and vulnerabilities emerge. Email providers must level up shields.
High-Speed Transmission Protocols
Finally, specialized infrastructure may arise to accelerate attachment routing speeds beyond legacy TCP email channels.
Similar to video streaming or large file transfer protocols, new transportation mechanisms designed specifically for fast direct secure attachment movement across networks could emerge.
Precedents like Aspera’s FASP shows speed-optimized protocols unlock 10-100X performance gains compared to traditional TCP shuffling.
Large attachments over 100GB increasingly necessitate such speed-centric distribution pipelines tailored to binary payloads. Email alone can’t cut it. But companion infrastructures could deliver.
The next wave of specialized attachment handling innovation seems targeted at maximizing security, speed and scalability – while preserving simplicity for users.
Innovative Attachment Focused Services
Email’s tremendous utility partially stems from attachments conveniently sidestepping external file transfers.
As business needs for securely sharing attachments balloon, specialized services catering to those use cases emerged. Let’s explore a few leading the way evolving attachments specifically for business contexts.
Mutant Mail’s Secure File Sharing
For organizations handling confidential documents and data, attachments pose hidden exposure risks without proper controls.
Mutant Mail mitigates this by combining privacy-focused email under your owned domain with enterprise-grade security scanning, archiving, eDiscovery capabilities and two-way routing.
This grants companies total visibility and control over how attachments enter and exit environments to prevent leakage or compliance violations.
Custom DLP policies, sandbox detonations, and full administrative access ensures organizations retain tight oversight governing sensitive attachments. Absolute separation from ad-driven webmail providers facilitates locking down flows.
For privacy-minded businesses or regulated industries like legal and healthcare, Mutant Mail enables safely sharing attachments without relinquishing data autonomy.
DoYouMail Optimizes Campaign Deliverability
Email marketing and sales teams conversely need to maximize exposure and engagement with attachment-based campaigns at high volume.
Unique compliance infrastructures allow the DoYouMail solution specialization to assist with orchestrating attachment-heavy sequenced messaging. Multi-step automations attach files to cold outreach, personalizing pitches while optimizing inbox delivery.
DoYouMail warms each automated email’s address through proprietary tools before blasting campaigns to guarantee attachments consistently reach target recipient inboxes without manifesting as spam.
Success dashboard reporting provides marketers critical attachment open and clickthrough analytics to refine strategies on the fly based on real user signals.
Mystrika’s Specialized Warmup Service
A void still exists however between ordinary ESP deliverability and full-fledged marketing automation platforms in the SMB realm.
Mystrika offers an interim solution concentrating specifically on improving attachment access from cold outreach emails.
Mystrika subscribers forward any cold messaging address to route through Mystrika’s optimized warmup queue first before sending the attachment-laden outreach. This preparatory warming smooths delivery rates when eventually contacting prospects.
Advanced users can even A/B test different attachment variations across customer groups to determine ideal configurations yielding maximum engagement.
Together these complementary services tackle optimized attachment experiences from distinct but equally important business communication perspectives.
Key Takeaways on Email Attachments
If absorbing all the nitty-gritty details around attachments feels overwhelming, don’t lose sight of a few core principles to guide your usage:
- Attachments enable easily sharing files via email instead of hassling with external transfers or cloud storage. This simplicity and convenience fuels tremendous productivity.
- However, size limits frequently interrupt large attachments from seamlessly sending cross-domain. Accessing underlying mail servers directly or integrating adjacent cloud storage helps sidestep barriers.
- Security requires balancing caution with practicality when opening attachments. Validate sources, leverage scanning tools, and limit device access to quarantine risks – but don’t avoid attachments altogether.
- Apply universal best practices around recipients, naming, compressing files, and compatibility checks to smooth out the mechanics of attaching. Set your sharing up for success!
- Continued innovation around integrations, security protections, and transmission protocols aims to preserve attachment convenience while keeping capabilities aligned with modern demands.
Email attachments represented an innovative leap forward for digital communication and collaboration when first introduced. But there remains ample room for the capability to continue maturing in multiple dimensions to meet emerging business needs.
At the end of the day, what matters most is that users grasp the overall value attachments provide, yet approach usage judiciously. Mixing this balanced mentality with ongoing technical advances paves an exciting road ahead for this ubiquitously relied upon email feature!
Frequently Asked Questions About Email Attachments
Still hungry for more email attachment knowledge? This comprehensive FAQ addresses the top questions that arise around capabilities, compatibility, security, and usage best practices.
What file types can be attached to emails?
Virtually any digital file can be attached thanks to MIME encoding – documents, spreadsheets, presentations, photos, audio, video, archives, installers, and more.
Do attachments increase email size?
Yes, attachments contribute to total email size. Also be aware that base64 encoding used for transmitting binary attachments increases files by ~37%. A 20MB file becomes ~28MB attached.
What attachments should I avoid sending?
Avoid obviously dangerous file types that could activate malware like EXE, DLL, JS, VBS files. Also avoid enfocing your own software dependencies without warning by attaching files requiring specialized viewers the recipient may lack.
What is the maximum attachment size for emails?
SMTP protocol doesn’t restrict sizes but email providers and servers commonly cap attachments at 25MB or less. Accessing mail servers directly sometimes allows bypassing limits. Also consider linking large files from cloud storage instead of attaching.
How can I send large attachments?
If attachments exceed size restrictions, try using cloud storage instead. Upload the file to Google Drive, Dropbox, etc. and share access permission via links in the email body as an alternative to attaching directly.
Why do attachments sometimes get blocked or filtered?
Overly large attachments may hit size filters as noted above. Suspicious file types also commonly get blocked by security filters aimed at stopping malware threats. Filters tend to lock down environments at the cost of occasionally blocking legitimate attachments as well.
Is it safe to open attachments from people I know?
Exercise caution before opening any attachments, even from familiar contacts. Accounts do get compromised. Verify legitimacy through alternate channels before enabling attachments from untrusted inboxes.
How can I share attachments with people securely?
If transmitting sensitive documents, confirm you have the right recipient list before attaching files to avoid accidental data leaks. Also utilize security controls like sandbox detonations, DLP policies, and archiving available through secure enterprise mail services.
What is the best format to send document attachments?
Aim for most universally compatible formats when attaching documents. PDF retains formatting consistently across devices compared to native Office documents. Also provide options like attaching both PDF and DOC files if feasible to maximize usability.