Experts only

Rollback
The number of bytes that will be requested from the remote user that overlap the existing incomplete file on disk. The overlapping bytes are compared, and if they do not match, the source is judged to be incompatible, and is removed with a "Rollback inconsistency, existing file does not match the one being downloaded" error. This value normally has no effect when Advanced Resume is enabled. (default: 4096)
Max Hash Speed
This is the speed at which DC++ will hash your files, in MiB/s. It is limited by the speed of your disk subsystem, but it can be used to make hashing slower and less noticable. A "normal" hash speed may be anywhere from 20 to 30 MiB/s. (no default)
PM history
The number of lines that will be read from the private message log and displayed when a new PM is received. (no default)
Mini slot size
This defines the size of the mini slot. The minimum value for this setting is 64 KiB. (default: 64 KiB)
Max filelist size
This setting controls the size of the maximum file list that DC++ will open, in mebibytes. This setting helps protect against malformed file lists that require large amounts of memory to decode.  You may need to reduce or increase the value of this setting based on personal experience. (default: 512 MiB)
CID
This is your unique client ID (CID) used to identify you on ADC hubs.
Auto refresh time
This controls the interval at which your shared directories are rescanned for new and changed content.  This is measured in minutes (default: 60 minutes)
Write Buffer Size
This controls the size of the chunks that DC++ writes to disk for downloads. Measured in kibibytes. (default: 16 KiB)
Max Tab Rows
The maximum number of rows of tabs that DC++ will make. Any tabs that do not fit will be accessible through the chevron at the right of the tab control. (default: 2)
Search history
Number of old search lines that will be shown in the Search Window. (default: 10)
Bind address
This setting allows you to bind DC++ to a particular IP address on your machine. Most users do not need to change the default value, 0.0.0.0. However, if you have more than one network interface connected to the internet, you can force DC++ to use a particular connection by entering its IP here. If binding fails, it will do so silently and INADDR_ANY will be used instead. If you experience connection problems make sure that this is set to default. (default: 0.0.0.0)
This feature requires a restart to be fully effective.
Socket read buffer
The size of the buffer DC++ use to read sockets. Measured in bytes. (default: 8192 bytes)
Socket write buffer
The size of the buffer DC++ use to write to sockets. Measured in bytes. (default: 8192 bytes)