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Frequently Asked Questions

  1. Does Underpass save chat transcripts to my Mac?

    No, Underpass does not currently support chat transcripts. This feature is being considered for a future Underpass update.

    All chat messages, including downloaded files, currently exist only in the chat window, and they disappear when you select "Clear Messages" or quit Underpass. After you quit Underpass, there will be no record of your chat in memory or on disk.

    You can manually save downloaded files to disk. See Save received files for more information. You can also copy and paste or drag and drop chat messages to another app.

  2. Can I chat with more than one device simultaneously?

    You can chat with more than one device simultaneously in separate chat windows. You cannot chat with more than one device in the same chat window. Underpass does not support group chat, and there are no plans to support group chat in the future. Each chat includes only your Mac and one other device.

  3. Can I connect to a link-local or private network IP address?

    Yes, Underpass recognizes any kind of IPv4 or IPv6 address, including the ranges 169.254.0.0/16 and 10.0.0.0/8 and fe80::/10. You would need to use an internet chat with these addresses.

    The terms "Local Area Network Chat" and "Internet Chat" in Underpass are not entirely accurate. The reason for the names is that most people recognize the terms LAN and internet, but fewer people are familiar with Bonjour service discovery and IP addresses. More precisely, LAN chats use Bonjour, and internet chats use IP addresses. Therefore, if you want to connect to an IP address, you would use an internet chat, regardless of whether the IP address is on the internet or on a LAN.

  4. Is there an iOS version of Underpass?

    Yes, Underpass for iOS devices — iPhone, iPad, iPod touch — is available for sale separately in the iOS App Store.

  5. Are there versions of Underpass for Android, Windows, or other platforms?

    At this time there are no plans for Underpass on Android, Windows, or any platform other than Mac and iOS.

  6. Is Underpass sandboxed?

    Yes, Underpass is sandboxed.

    The sandbox entitlements include allowances for incoming and outgoing network connections, which are necessary for chats.

  7. Does Underpass "phone home"?

    No, Underpass never phones home.

    Your chats are completely independent of the developer of Underpass and never go through the developer's computers. No communication of any kind ever occurs between Underpass and the developer. This promise can be verified by taking traces of Underpass network packets.

    There are links in Contact support to open the Underpass web site in your browser or email Underpass support, but you have to click those links manually.

  8. What encryption algorithm does Underpass use?

    Underpass uses the Advanced Encryption Standard algorithm with a 128 bit key size (AES-128) See Passwords and encryption for more information.

  9. Is Underpass open source?

    No, Underpass is not open source, and there are no plans to open the source code.

  10. Who is the Underpass developer?

    My name is Jeff Johnson. (Yes, that's my real name, not a generic pseudonym.) I've been a developer on Apple platforms for over a decade. I'm fairly well known in the Apple developer community, but I'm not otherwise famous. I'm not a large corporation. I'm not backed by venture capital. I don't sell advertising. I'm not a government agent. I'm just an independent developer, and I thank you for your business!

Next: Troubleshooting

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