Tor will use an unconfigured bridge if it was a configured bridge last time you ran Tor
If you configure your Tor client with
usebridges 1
bridge 128.31.0.34:9009and you run it and it works, then Tor will end up writing two things to disk: 1) a @purpose bridge descriptor for 128.31.0.34 in your cached-descriptors file:
@downloaded-at 2011-02-08 07:54:52
@source "128.31.0.34"
@purpose bridge
router bridge 128.31.0.34 9009 0 0
...and 2) an entry guard stanza in your state file:
EntryGuard bridge 4C17FB532E20B2A8AC199441ECD2B0177B39E4B1
EntryGuardAddedBy 4C17FB532E20B2A8AC199441ECD2B0177B39E4B1 0.2.3.0-alpha-dev 2011-02-01 18:43:23Then if you kill your Tor and run it with
usebridges 1
bridge 150.150.150.150:9009it will successfully bootstrap -- using the bridge that worked before but isn't your requested bridge.
To upload designs, you'll need to enable LFS and have admin enable hashed storage. More information