From DSL Wiki
This file stores the DSL mirror used to download DSL files, such as myDSL extensions.
The dslMirror program gives the user a gui access to this file.
The default file looks like this:
Mirror: www.ibiblio.org/pub/linux/distributions/damnsmall/ Protocol: http
However, the ibiblio mirror has moved sudbomain and this causes some scripts (notably dpkg-install) to fail. A better configuration is:
Mirror: distro.ibiblio.org/pub/linux/distributions/damnsmall/ Protocol: http