Questions relating to bridge relays, their maintenance and operation.
Bridge relays (or "bridges" for short) are Tor relays that aren't listed in the main Tor directory. Since there is no complete public list of them, even if your ISP is filtering connections to all the known Tor relays, they probably won't be able to block all the bridges. If you suspect your access to the Tor network is being blocked, you may want to use the bridge feature of Tor.
More information: https://www.torproject.org/docs/bridges