Two-factor authentication: adding another sign-in requirement
Short answer: Two-factor authentication requires a second category of evidence alongside the primary login secret. The extra check reduces the risk from a password being stolen.
Keep the recovery options provided by the service accessible. Phone-based checks also depend on maintaining control of the linked number, so renewal and account security still matter.
Use the definition to check your setup
Two-factor authentication requires a second category of evidence alongside the primary login secret. The extra check reduces the risk from a password being stolen.
Keep the recovery options provided by the service accessible. Phone-based checks also depend on maintaining control of the linked number, so renewal and account security still matter.
Two-factor authentication: adding another sign-in requirement — points to check
| Review point | CallGlobal guidance |
|---|---|
| Concept | Two-factor authentication requires a second category of evidence alongside the primary login secret. The extra check reduces the risk from a password being stolen. |
| Configuration implication | Keep the recovery options provided by the service accessible. Phone-based checks also depend on maintaining control of the linked number, so renewal and account security still matter. |
| Product boundary | Consult the feature list; a glossary term does not identify an included capability. |
Where the CallGlobal line fits
Your number account provides the public telephone identity, its communication controls and the SIP credentials for compatible software. Other capabilities belong to the application or phone system you choose.
Review the live product feature list before relying on an additional function. Number porting, hosted IVR, voicemail, call recording and a public customer API are not included.
Protect the line and the account
- Keep account and SIP passwords private, including in support screenshots.
- Confirm the active rental term before relying on incoming communication.
- Use the complete international number and only an authorized caller identity.
Frequently asked questions
What does this term describe?
Two-factor authentication requires a second category of evidence alongside the primary login secret. The extra check reduces the risk from a password being stolen.
How does this affect practical configuration?
Keep the recovery options provided by the service accessible. Phone-based checks also depend on maintaining control of the linked number, so renewal and account security still matter.
Does every telephone concept name an included product feature?
No. A glossary explains terminology. The product feature page and your number dashboard identify the functions provided with a CallGlobal line.
Continue exploring
- one-time passwords
- SMS verification
- mobile numbers
- account security
- privacy use case
- Google account verification
- Toll-free ranges: understanding the national calling arrangement
- Virtual numbers: telephone access beyond a single SIM
Sources
- NIST: SP 800-63B Digital Identity Guidelines, Authentication (as of September 2026)
- IETF: RFC 6238, TOTP: Time-Based One-Time Password Algorithm (as of September 2026)