I ran network-admin with dbus-monitor running. I'm not sure if this offers any useful information, but here's the output:

signal sender=org.freedesktop.DBus -> dest=(null destination) path=/org/freedesktop/DBus; interface=org.freedesktop.DBus; member=NameOwnerChanged
   string ":1.119"
   string ""
   string ":1.119"
method call sender=:1.119 -> dest=org.freedesktop.DBus path=/org/freedesktop/DBus; interface=org.freedesktop.DBus; member=Hello
signal sender=org.freedesktop.DBus -> dest=(null destination) path=/org/freedesktop/DBus; interface=org.freedesktop.DBus; member=NameOwnerChanged
   string ":1.120"
   string ""
   string ":1.120"
method call sender=:1.120 -> dest=org.freedesktop.DBus path=/org/freedesktop/DBus; interface=org.freedesktop.DBus; member=Hello
method call sender=:1.120 -> dest=org.gtk.vfs.Daemon path=/org/gtk/vfs/mounttracker; interface=org.gtk.vfs.MountTracker; member=listMountableInfo
method return sender=:1.8 -> dest=:1.120 reply_serial=2
   array [
      struct {
         string "ftp"
         string "ftp"
         array [
         ]
         int32 21
         boolean true
      }
      struct {
         string "archive"
         string "archive"
         array [
         ]
         int32 0
         boolean false
      }
      struct {
         string "burn"
         string "burn"
         array [
         ]
         int32 0
         boolean false
      }
      struct {
         string "computer"
         string "computer"
         array [
         ]
         int32 0
         boolean false
      }
      struct {
         string "dav"
         string "dav"
         array [
         ]
         int32 0
         boolean false
      }
      struct {
         string "cdda"
         string "cdda"
         array [
         ]
         int32 0
         boolean false
      }
      struct {
         string "dns-sd"
         string "dns-sd"
         array [
         ]
         int32 0
         boolean false
      }
      struct {
         string "obex"
         string "obex"
         array [
         ]
         int32 0
         boolean false
      }
      struct {
         string "network"
         string "network"
         array [
         ]
         int32 0
         boolean false
      }
      struct {
         string "smb-share"
         string "smb"
         array [
         ]
         int32 0
         boolean false
      }
      struct {
         string "localtest"
         string "localtest"
         array [
         ]
         int32 0
         boolean false
      }
      struct {
         string "http"
         string "http"
         array [
         ]
         int32 0
         boolean false
      }
      struct {
         string "trash"
         string "trash"
         array [
         ]
         int32 0
         boolean false
      }
      struct {
         string "smb-server"
         string "smb"
         array [
         ]
         int32 0
         boolean false
      }
      struct {
         string "smb-network"
         string "smb"
         array [
         ]
         int32 0
         boolean false
      }
      struct {
         string "sftp"
         string "sftp"
         array [
            string "ssh"
         ]
         int32 22
         boolean true
      }
   ]