Understanding Universal Acceptance (UA) and Technical Challenges

Understanding Universal
Acceptance (UA) and Technical
Challenges
by Joyeeta Sen Rimpee
Manager (Technical), Domain Division, BTCL

Domain names
• New short top-level ASCII domain names: example.sky
• New long top-level ASCII domain names: example.engineering
• Internationalized Domain Names (IDNs): বিটিসিএল.বাংলা
Email addresses
• ASCII@ASCII (new and long TLD) ekrem@misal.istanbul
• ASCII@IDN marc@société.org
• Unicode@ASCII 测试 @example.com
• Unicode@IDN যোগাযোগ@বিটিসিএল.বাংলা
• Unicode@IDN; right-to-left scripts ‫موقع‬.‫ايميل@مثال‬
What Does UA Address Technically?
Universal Acceptance addresses an issue that prevents some Internet users from successfully completing
communications online. The problem can arise when applications reject or cannot treat all domain names or
email addresses properly.
Examples of Domain and Email

Not UA-Ready vs US-Ready
Total 2566 Domain were registered in .বাংলা but only 366 domains are active now due to Non UA ready.

Overcoming UA Technical Challenges

IDN DNS Technical Mechanism
Internationalized Domain Names rely on Punycode encoding for DNS compatibility. This technical mechanism converts Unicode
characters into ASCII-compatible encoding (ACE) for the Domain Name System, which still operates on ASCII principles following the
Letter-Digit-Hyphen (LDH) rule.
1
User Input
User enters IDN in native script (বিটিসিএল.বাংলা)
2
Encoding
System converts to Punycode (xn--
j5b5azb0a2a4bbb.xn--54b7fta0cc)
3
DNS Resolution
DNS processes the ASCII-compatible encoded
version
4
Display
Application converts back to native script for
user display

Domain Name Challenges (IDNs)
Punycode Complexity
IDNs convert to unreadable ASCII
(e.g., বাংলাদেশ.বাংলা → xn--
54b7fta0ccf0d.xn--54b7fta0cc).
Impact: Confuses users in DNS
settings or registrations.
Validation Errors
Many systems use ASCII-only regex,
rejecting valid IDNs. Example: A
form blocks নিউজ.বাংলা, labeling it
"invalid."
Homoglyph & Phishing
Risks
Visually similar characters (e.g.,
ɦংলাদেশ.বাংলা vs. বাংলাদেশ.বাংলা)
enable spoofing.
Solutions
• Adopt Unicode-Aware Validation (RFC 5891)
• Display Native Script (Not Punycode) in UIs
• Implement Homoglyph Detection (e.g., Unicode confusables tables)

Hosting & Infrastructure Barriers
Limited Control Panel
Support
cPanel/Plesk often require
Punycode input. Example: Users
must manually enter xn--
l2b7bxfcc5c.xn--54b7fta0cc
instead of আমারসাইট.বাংলা.
SSL/TLS Certificate Issues
Some CAs fail to validate IDNs
unless submitted as Punycode.
DNS & Server
Misconfigurations
NGINX/Apache may mishandle
IDN redirects.
Solutions
• Hosting Providers: Add native-script input fields.
• CAs: Improve IDN validation workflows.
• DevOps Teams: Use UTF-8 encoding in configs.

Email Challenges (EAI)
Low EAI Adoption
Major providers (Gmail, Outlook) inconsistently support EAI.
Example: রাহুল@নিউজ.বাংলা bounces when sent to Gmail.
Client-Side Limitations
Email clients (e.g., Outlook) may reject non-ASCII addresses.
Silent SMTPUTF8 Failures
Emails drop without clear errors if intermediaries lack EAI
support.
Solutions
• Enable SMTPUTF8 in mail servers (Postfix, Exchange).
• Test EAI with tools like ICANN's EAI Tester.

Mobile & Cloud Apps Challenges
Failure Point
A news app rejects খবর.বাংলা due to
ASCII-only filters.
Technical Root
Legacy validation code fails to handle
Unicode properly.
Solution
Use UA-ready libraries (e.g., ICU for
Unicode).
Outcome
Apps become accessible to non-Latin
script users.
Mobile and cloud applications represent a critical frontier for Universal Acceptance implementation. As more users access
the internet primarily through mobile devices, ensuring these platforms properly handle internationalized domains and
email addresses becomes increasingly important.

Government & Public Services Impact (example 1)
Failure Case
Bangladeshi citizens cannot use জয়ীতা@ভূমি.বাংলা for tax portals.
Success Case
India's .भारत domains are mandated for e-governance (MeitY, 2017).
Government adoption of Universal Acceptance principles directly impacts citizens' ability to access essential services in their native languages. When
implemented correctly, it creates more inclusive digital governance.

Business & E-Commerce Impact (example 2)
1
Barrier
PayPal blocks ডোমেইন.বাংলা in merchant URLs.
2
Challenge
Businesses lose local customers when payment systems reject IDNs.
3
Success
Russian businesses using .рф saw higher local engagement (Ru-Center,
2023).
The business impact of Universal Acceptance extends beyond technical considerations to directly affect market reach and customer experience. Companies
that embrace multilingual domains can better connect with local markets and build trust with non-English speaking customers.

UA Compliance Checklist for Developers
Area Action Item
Database Use utf8mb4 (MySQL) or UTF-8 (PostgreSQL).
Validation Replace ASCII regex with p{L} (Unicode letters).
Email Enable SMTPUTF8 in Postfix/Exchange.
Security Deploy homoglyph detection + DNSSEC for IDNs.
Developers play a crucial role in implementing Universal Acceptance at the technical level. By following this checklist, they can ensure their
systems properly handle internationalized domain names and email addresses, creating more inclusive digital experiences.

Environment Configurations Used for Testing
Web Hosting Tool OS Web Server version Email Server Database
cPanel 104.0.7
Rocky Linux 8.6 (Green
Obsidian)
Apache 2.4.54
Exim 4.95 (Dovecot
2.3.18)
MySQL 8.0.29 for Linux on
x86_64 (MySQL Community
Server - GPL)
Ubuntu 20.04 LTS Apache 2.4.54
Exim 4.95 (Dovecot
2.3.18)
Server - GPL)
CentOS Linux 7 (Core) Apache 2.4.54
Exim 4.95 (Dovecot
2.3.18)
MySQL 5.7.38, for Linux (x86_64)
using EditLine wrapper
Plesk Obsidian Web Host
Edition Version 18.0.45
AlmaLinux 8.6 (Sky Tiger)
Apache 2.4.37 - serves Plesk
admins and resellers
nginx 1.20.2 - serves end
users
Postfix 3.5.14 (Dovecot
2.3.18)
MariaDB 10.3-32, for Linux
(x86_64) using readline 5.1
Debian GNU/Linux 11
(bullseye)
Apache 2.4.54 - serves Plesk
admins and resellers
nginx 1.20.2 - serves end
users
Postfix 3.5.13 (Dovecot
2.3.18)
MariaDB 10.5-15, for debian-
linux-gnu (x86_64) using EditLine
wrapper -for Plesk management
PostgreSQL 13.7 - for end users
Windows 10 Microsoft IIS 10.0
MailEnable Standard
10.34
MariaDB 10.6
ISPConfig 3.2.2
openSUSE Leap 15.4 Apache 2.4.51
Exim 4.94.2 (Dovecot
2.3.15)
Server - GPL)
Oracle Linux Server 8.6 Apache 2.4.37 Postfix 3.5.8
x86_64 (Source distribution)
Fedora Linux 36 (Server
Edition)
Apache 2.4.54 Postfix 3.6.4
MariaDB 10.5-16, for Linux
(x86_64) using EditLine wrapper
Source: Measuring the Universal Acceptance (UA) Readiness of Popular Web Hosting Tools (UASG 042)

Test Results: Overall Test Scenario Status
Source: Measuring the Universal Acceptance (UA) Readiness of Popular Web Hosting Tools (UASG 042)

Building an Inclusive Internet
Audit Systems
Developers: Audit systems using UASG's
Tools.
Enforce Standards
Governments: Enforce UA in public-sector
software.
Leverage Market Opportunities
Businesses: Leverage IDNs to reach new
markets (e.g., দোকান.বাংলা).
UA is not optional—it's essential for a multilingual internet. From .বাংলা to .рф, success stories show that technical compliance +
policy enforcement drives adoption.
By closing UA gaps, we ensure no user is left behind.
References:
• ICANN (2023). Universal Acceptance Report. Link
• UASG (2022). UA Developer's Guide. Link
• MeitY (2020). Digital India Progress Report. Link

Current Configuration of Email Server with .বাংলা
1. Domain: বিটিসিএল.বাংলা
2. Technology used:
a) Authoritative DNS: Bind
b) OS: Ubuntu
c) MTA: Postfix
d) MDA: Dovecot
MUA: Roundcube
e) SSL certificate: Let's Encrypt

We successfully exchanged email with IDN email address in occasion of
UA Day in Bangladesh on 15 April 2025 But we are not ready.

Thank you
জয়ীতা@বিটিসিএল.বাংলা

Understanding Universal Acceptance (UA) and Technical Challenges

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