Synchronet v3.18b-Win32 (install) has been released (Sept-2020).

Synchronet v3.19a, now under development, requires libarchive-dev to build successfully.

You can donate to the Synchronet project using PayPal.

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Table of Contents


LetSyncrypt is a Let's Encrypt client for Synchronet which uses the ACMEv2 protocol.


LetSyncrypt should be added as a timed event.

Add the Timed Event in SCFG->External Programs->Timed Events:

Internal Code                   SYNCRYPT
Start-up Directory
Command Line                    ?letsyncrypt.js
Enabled                         Yes
Execution Node                  1
Execution Months                Any
Execution Days of Month         Any
Execution Days of Week          All
Execution Frequency             1 times a day
Requires Exclusive Execution    No
Force Users Off-line For Event  No
Native Executable               No
Use Shell to Execute            No
Background Execution            No
Always Run After Init/Re-init   Yes

If you have multiple domain names, you can have LetSyncrypt put them all in a single certificate, even if you have virtual hosts. Edit the ctrl/letsyncrypt.ini file and add a [Domains] section where the key is the hostname, and the value is the web root for that domain:


This example has four domains (,,, and The last two are virtual hosts, so have their web root as a subdirectory of the main web root.

You can specify the ACMEv2 endpoint using the Host and Directory keys in the root section. Host is the domain name of the ACMEv2 endpoint, and Directory is appended to it to generate the URL that is fetched for the Directory object. You can also indicate that you agree to the Terms of Service by setting TOSAgreed to true.

Note that without the TOSAgreed=true line, you will likely never get a certificate, but the first few words in this file at present are “This Subscriber Agreement (“Agreement”) is a legally binding contract”

Do not modify the State or key_id sections of this file.

Running Manually

You can also run the script using jsexec. It accepts a number of arguments:

--new-key Changes the account key

--force Forces a certificate renewal, ignoring the expiration date of the current certificate.

--revoke Revokes the current certificate, then obtains a new one.

--tos Prints the URL for the Terms of Service.

See Also

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